Pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione derivatives useful as inhibitors of phosphodiesterase 1

ABSTRACT

Optionally substituted (5- or 7-amino)-3,4-dihydro-(optionally 4-oxo, 4-thioxo or 4-imino)-1H-pyrrolo[3,4-d]pyrimidin-2(6H)-ones, Compounds of Formula I, processes for their production, their use as pharmaceuticals and pharmaceutical compositions comprising them.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a United States Application under 35 U.S.C. 371claiming benefit of PCT Application No. PCT/US2009/006443, filed on Dec.7, 2009, which claims the benefit of U.S. Provisional Application Nos.61/120,444, filed on Dec. 6, 2008, and 61/235,888 filed on Aug. 21,2009, respectively, the contents of each of which are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to a compound of Formula I as describedbelow, processes for their production, their use as pharmaceuticals andpharmaceutical compositions comprising them. Of particular interest arenovel compounds useful as inhibitors of phosphodiesterase 1 (PDE1),e.g., in the treatment of diseases involving disorders of the dopamineD1 receptor intracellular pathway, such as Parkinson's disease,depression, narcolepsy, damage to cognitive function, e.g., inschizophrenia, or disorders that may be ameliorated through enhancedprogesterone-signaling pathway, e.g., female sexual dysfunction.

BACKGROUND OF THE INVENTION

Eleven families of phosphodiesterases (PDEs) have been identified butonly PDEs in Family I, the Ca²⁺-calmodulin-dependent phosphodiesterases(CaM-PDEs), have been shown to mediate both the calcium and cyclicnucleotide (e.g. cAMP and cGMP) signaling pathways. The three knownCaM-PDE genes, PDE1A, PDE1B, and PDE1C, are all expressed in centralnervous system tissue. PDE is expressed throughout the brain with higherlevels of expression in the CA1 to CA3 layers of the hippocampus andcerebellum and at a low level in the striatum. PDE1A is also expressedin the lung and heart. PDE1B is predominately expressed in the striatum,dentate gyrus, olfactory tract and cerebellum, and its expressioncorrelates with brain regions having high levels of dopaminergicinnervation. Although PDE1B is primarily expressed in the centralnervous system, it may be detected in the heart. PDE1C is primarilyexpressed in olfactory epithelium, cerebellar granule cells, andstriatum. PDE1C is also expressed in the heart and vascular smoothmuscle.

Cyclic nucleotide phosphodiesterases decrease intracellular cAMP andcGMP signaling by hydrolyzing these cyclic nucleotides to theirrespective inactive 5′-monophosphates (5′AMP and 5′GMP). CaM-PDEs play acritical role in mediating signal transduction in brain cells,particularly within an area of the brain known as the basal ganglia orstriatum. For example, NMDA-type glutamate receptor activation and/ordopamine D2 receptor activation result in increased intracellularcalcium concentrations, leading to activation of effectors such ascalmodulin-dependent kinase II (CaMKII) and calcineurin and toactivation of CaM-PDEs, resulting in reduced cAMP and cGMP. Dopamine D1receptor activation, on the other hand, leads to activation ofnucleotide cyclases, resulting in increased cAMP and cGMP. These cyclicnucleotides in turn activate protein kinase A (PKA; cAMP-dependentprotein kinase) and/or protein kinase G (PKG; cGMP-dependent proteinkinase) that phosphorylate downstream signal transduction pathwayelements such as DARPP-32 (dopamine and cAMP-regulated phosphoprotein)and cAMP responsive element binding protein (CREB). PhosphorylatedDARPP-32 in turn inhibits the activity of protein phosphates-1 (PP-1),thereby increasing the state of phosphorylation of substrate proteinssuch as progesterone receptor (PR), leading to induction of physiologicresponses. Studies in rodents have suggested that inducing cAMP and cGMPsynthesis through activation of dopamine D1 or progesterone receptorenhances progesterone signaling associated with various physiologicalresponses, including the lordosis response associated with receptivityto mating in some rodents. See Mani, et al., Science (2000) 287: 1053,the contents of which are incorporated herein by reference.

CaM-PDEs can therefore affect dopamine-regulated and other intracellularsignaling pathways in the basal ganglia (striatum), including but notlimited to nitric oxide, noradrenergic, neurotensin, CCK, VIP,serotonin, glutamate (e.g., NMDA receptor, AMPA receptor), GABA,acetylcholine, adenosine (e.g., A2A receptor), cannabinoid receptor,natriuretic peptide (e.g., ANP, BNP, CNP), DARPP-32, and endorphinintracellular signaling pathways.

Phosphodiesterase (PDE) activity, in particular, phosphodiesterase 1(PDE1) activity, functions in brain tissue as a regulator of locomotoractivity and learning and memory. PDE1 is a therapeutic target forregulation of intracellular signaling pathways, preferably in thenervous system, including but not limited to a dopamine D1 receptor,dopamine D2 receptor, nitric oxide, noradrenergic, neurotensin, CCK,VIP, serotonin, glutamate (e.g., NMDA receptor, AMPA receptor), GABA,acetylcholine, adenosine (e.g., A2A receptor), cannabinoid receptor,natriuretic peptide (e.g., ANP, BNP, CNP), endorphin intracellularsignaling pathway and progesterone signaling pathway. For example,inhibition of PDE should act to potentiate the effect of a dopamine D1agonist by protecting cGMP and cAMP from degradation, and shouldsimilarly inhibit dopamine D2 receptor signaling pathways, by inhibitingPDE1 activity. Chronic elevation in intracellular calcium levels islinked to cell death in numerous disorders, particularly inneurodegerative diseases such as Alzheimer's, Parkinson's andHuntington's Diseases and in disorders of the circulatory system leadingto stroke and myocardial infarction. PDE1 inhibitors are thereforepotentially useful in diseases characterized by reduced dopamine D1receptor signaling activity, such as Parkinson's disease, restless legsyndrome, depression, narcolepsy and cognitive impairment. PDE1inhibitors are also useful in diseases that may be alleviated by theenhancement of progesterone-signaling such as female sexual dysfunction.

There is thus a need for compounds that selectively inhibit PDE1activity, especially PDE1A and/or PDE activity.

SUMMARY OF THE INVENTION

In the first embodiment, the invention provides a compound of Formula II

wherein

-   -   (i) L is S, SO or SO₂;    -   (ii) R₁ is H or C₁₋₆alkyl (e.g., methyl or ethyl);    -   (iii) R₂ is        -   H,        -   C₁₋₆alkyl (e.g., isopropyl, isobutyl, neopentyl,            2-methylbutyl, 2,2-dimethylpropyl) wherein said alkyl group            is optionally substituted with halo (e.g., fluoro) or            hydroxy (e.g., 1-hydroxypropan-2-yl,            3-hydroxy-2-methylpropyl),        -   —C₀₋₄-alkyl-C₃₋₈cycloalkyl (e.g., cyclopentyl, cyclohexyl)            optionally substituted with one or more amino (e.g., —NH₂),            for example, 2-aminocyclopentyl or 2-aminocyclohexyl),            wherein said cycloalkyl optionally contains one or more            heteroatom selected from N and O and is optionally            substituted with C₁₋₆alkyl (e.g., 1-methyl-pyrrolindin-2-yl,            1-methyl-pyrrolindin-3-yl, 1-methyl-pyrrolindin-2-yl-methyl            or 1-methyl-pyrrolindin-3-yl-methyl),        -   C₃₋₈heterocycloalkyl (e.g., pyrrolidinyl, for example,            pyrrolidin-3-yl) optionally substituted with C₁₋₆alkyl            (e.g., methyl), for example, 1-methylpyrrolidin-3-yl,        -   C₃₋₈cycloalkyl-C₁₋₆alkyl (e.g., cyclopropylmethyl),        -   haloC₁₋₆alkyl (e.g., trifluoromethyl, 2,2,2-trifluoroethyl),        -   —N(R₁₄)(R₁₅)—C₁₋₆alkyl (e.g.,            2-(dimethylamino)ethyl,2-aminopropyl),        -   hydroxyC₁₋₆alkyl (e.g., (e.g., 3-hydroxy-2-methylpropyl,            1-hydroxyprop-2-yl),        -   arylC₀₋₆alkyl (e.g., benzyl),        -   heteroarylC₁₋₆alkyl (e.g., pyridinylmethyl),        -   C₁₋₆alkoxyarylC₁₋₆alkyl (e.g., 4-methoxybenzyl);        -   -G-J wherein:            -   G is a single bond or, alkylene (e.g., methylene);            -   J is cycloalkyl or heterocycloalkyl (e.g., oxetan-2-yl,                pyrolyin-3-yl, pyrolyin-2-yl) optionally substituted                with C₁₋₆alkyl (e.g., (1-methylpyrrolidin-2-yl));    -   (iv) R₃ is attached to one of the nitrogens on the pyrazolo        portion of Formula I and is a moiety of Formula A

-   -   -   wherein X, Y and Z are, independently, N or C, and R₈, R₉,            R₁₁ and R₁₂ are independently H or halogen (e.g., Cl or F);        -   and R₁₀ is            -   halogen,            -   C₁₋₆alkyl,            -   C₃₋₈cycloalkyl,            -   heteroC₃₋₈cycloalkyl (e.g., pyrrolidinyl or piperidinyl)            -   haloC₁₋₆alkyl (e.g., trifluoromethyl),            -   aryl (e.g., phenyl),            -   heteroaryl (e.g., pyridyl, (for example, pyrid-2-yl) or                e.g., thiadiazolyl (for example, 1,2,3-thiadiazol-4-yl),                diazolyl, triazolyl (e.g., 1,2,4-triazol-1-yl),                tetrazolyl (e.g., tetrazol-5-yl), alkoxadiazolyl (e.g.,                5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g.,                pyrazol-1-yl),            -   alkyl sulfonyl (e.g., methyl sulfonyl),            -   arylcarbonyl (e.g., benzoyl), or            -   heteroarylcarbonyl,            -   alkoxycarbonyl, (e.g., methoxycarbonyl),            -   aminocarbonyl;            -   preferably phenyl, pyridyl, e.g., 2-pyridyl,                piperidinyl, or pyrrolidinyl;            -   wherein the aryl, heteroaryl cycloalkyl or                heterocycloalkyl is optionally substituted with one or                more halo (e.g., F or Cl), C₁₋₄alkyl, C₁₋₄alkoxy,                C₁₋₄haloalkyl (e.g., trifluoromethyl), and/or —SH,            -   provided that when X, Y or X is nitrogen, R₈, R₉ or R₁₀,                respectively, is not present;

    -   (v) R₄ is        -   H,        -   C₁₋₆alkyl (e.g., methyl, isopropyl),        -   C₃₋₈cycloalkyl (e.g., cyclopentyl),        -   C₃₋₈heterocycloalkyl (e.g., pyrrolidin-3-yl),        -   aryl (e.g., phenyl) or heteroaryl (e.g., pyrid-4-yl,            pyrid-2-yl or pyrazol-3-yl) wherein said aryl or heteroaryl            is optionally substituted with halo (e.g., 4-fluorophenyl),            hydroxy (e.g., 4-hydroxyphenyl), C₁₋₆alkyl, C₁₋₆alkoxy or            another aryl group (e.g., biphenyl-4-ylmethyl);

    -   (vi) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl,        in free or salt form.

In still another embodiment, the invention provides a Compound ofFormula II as described above, wherein

-   -   R₄ is:        -   C₁₋₆alkyl (e.g., methyl, isopropyl),        -   C₃₋₈cycloalkyl (e.g., cyclopentyl),        -   C₃₋₈heterocycloalkyl (e.g., pyrrolidin-3-yl),        -   aryl (e.g., phenyl) or heteroaryl (e.g., pyrid-4-yl,            pyrid-2-yl or pyrazol-3-yl) wherein said aryl or heteroaryl            is optionally substituted with halo (e.g., 4-fluorophenyl),            hydroxy (e.g., 4-hydroxyphenyl), C₁₋₆alkyl, C₁₋₆alkoxy or            another aryl group (e.g., biphenyl-4-ylmethyl);    -   and    -   R₃ is attached to one of the nitrogens on the pyrazolo portion        of Formula I and is a moiety of Formula A

-   -   -   wherein X, Y and Z are, independently, N or C, and R₈, R₉,            R₁₁ and R₁₂ are independently H or halogen (e.g., Cl or F);        -   and R₁₀ is        -   C₃₋₈cycloalkyl            -   heteroC₃₋₈cycloalkyl (e.g., pyrrolidinyl or piperidinyl)            -   aryl (e.g., phenyl), or            -   heteroaryl (e.g., pyridyl, (for example, pyrid-2-yl) or                e.g., thiadiazolyl (for example, 1,2,3-thiadiazol-4-yl),                diazolyl, triazolyl (e.g., 1,2,4-triazol-1-yl),                tetrazolyl (e.g., tetrazol-5-yl), alkoxadiazolyl (e.g.,                5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g.,                pyrazol-1-yl),            -   wherein the aryl or heteroaryl is optionally substituted                with one or more halo (e.g., F or Cl), C₁₋₄alkyl,                C₁₋₄alkoxy, C₁₋₄haloalkyl (e.g., trifluoromethyl),                and/or —SH,            -   provided that when X, Y or X is nitrogen, R₈, R₉ or R₁₀,                respectively, is not present;                in free or salt form.

The invention also provides a compound of formula I

wherein

-   -   (i) L is S, SO or SO₂;    -   (ii) R₁ is H or C₁₋₆alkyl (e.g., methyl or ethyl);    -   (iii) R₂ is        -   H,        -   C₁₋₆alkyl (e.g., isopropyl, isobutyl, neopentyl,            2-methylbutyl, 2,2-dimethylpropyl) wherein said alkyl group            is optionally substituted with halo (e.g., fluoro) or            hydroxy (e.g., 1-hydroxypropan-2-yl,            3-hydroxy-2-methylpropyl),        -   —C₀₋₄-alkyl-C₃₋₈cycloalkyl (e.g., cyclopentyl, cyclohexyl)            optionally substituted with one or more amino (e.g., —NH₂),            for example, 2-aminocyclopentyl or 2-aminocyclohexyl),            wherein said cycloalkyl optionally contains one or more            heteroatom selected from N and O and is optionally            substituted with C₁₋₆alkyl (e.g., 1-methyl-pyrrolindin-2-yl,            1-methyl-pyrrolindin-3-yl, 1-methyl-pyrrolindin-2-yl-methyl            or 1-methyl-pyrrolindin-3-yl-methyl),        -   C₃₋₈heterocycloalkyl (e.g., pyrrolidinyl, for example,            pyrrolidin-3-yl) optionally substituted with C₁₋₆alkyl            (e.g., methyl), for example, 1-methylpyrrolidin-3-yl,        -   C₃₋₈cycloalkyl-C₁₋₆alkyl (e.g., cyclopropylmethyl),            haloC₁₋₆alkyl (e.g., trifluoromethyl, 2,2,2-trifluoroethyl),        -   —N(R₁₄)(R₁₅)—C₁₋₆alkyl (e.g.,            2-(dimethylamino)ethyl,2-aminopropyl),        -   hydroxyC₁₋₆alkyl (e.g., (e.g., 3-hydroxy-2-methylpropyl,            1-hydroxyprop-2-yl),        -   arylC₀₋₆alkyl (e.g., benzyl),        -   heteroarylC₁₋₆alkyl (e.g., pyridinylmethyl),        -   C₁₋₆alkoxyarylC₁₋₆alkyl (e.g., 4-methoxybenzyl);        -   -G-J wherein:            -   G is a single bond or, alkylene (e.g., methylene);            -   J is cycloalkyl or heterocycloalkyl (e.g., oxetan-2-yl,                pyrolyin-3-yl, pyrolyin-2-yl) optionally substituted                with C₁₋₆alkyl (e.g., (1-methylpyrrolidin-2-yl));    -   (iv) R₃ is        -   1) -D-E-F wherein:            -   D is a single bond, C₁₋₆alkylene (e.g., methylene), or                arylalkylene (e.g., pbenzylene or —CH₂C₆H₄—);            -   E is                -   a single bond,                -   C₁₋₄alkylene (e.g., methylene, ethynylene,                    prop-2-yn-1-ylene),                -   —C₀₋₄alkylarylene (e.g., phenylene or —C₆H₄—,                    -benzylene- or —CH₂C₆H₄—), wherein the arylene group                    is optionally substituted with halo (e.g., Cl or F),                -   heteroarylene (e.g., pyridinylene or                    pyrimidinylene),                -   aminoC₁₋₆alkylene (e.g., —CH₂N(H)—),                -   amino (e.g., —N(H)—);                -   C₃₋₈cycloalkylene optionally containing one or more                    heteroatom selected from N or O (e.g.,                    piperidinylene),            -   F is                -   H,                -   halo (e.g., F, Br, Cl),                -   C₁₋₆alkyl (e.g., isopropyl or isobutyl),                -   haloC₁₋₆alkyl (e.g., trifluoromethyl),                -   aryl (e.g., phenyl),                -   C₃₋₈cycloalkyl optionally containing at least one                    atom selected from a group consisting of N or O                    (e.g., cyclopentyl, cyclohexyl, piperidinyl,                    pyrrolidinyl, tetrahydro-2H-pyran-4-yl, or                    morpholinyl), and optionally substituted with                    C₁₋₆alkyl (e.g., methyl or isopropyl), for example,                    1-methylpyrrolidin-2-yl, pyrrolidin-1-yl,                    pyrrolidin-2-yl, piperidin-2-yl,                    1-methylpiperidin-2-yl, 1-ethylpiperidin-2-yl,                -   heteroaryl optionally substituted with C₁₋₆alkyl,                    (e.g., pyridyl, (for example, pyrid-2-yl),                    pyrimidinyl (for example, pyrimidin-2-yl,                    pyrimidin-4-yl), thiadiazolyl (for example,                    1,2,3-thiadiazol-4-yl), oxazolyl (e.g.,                    oxazol-2-yl), diazolyl (e.g., pyrazolyl (for                    example, pyrazol-1-yl) or imidazolyl (for example,                    imidazol-1-yl, 4-methylimidazolyl,                    1-methylimidazol-2-yl,), triazolyl (e.g.,                    1,2,4-triazol-1-yl), tetrazolyl (e.g.,                    tetrazol-5-yl), alkoxadiazolyl (e.g.,                    5-methyl-1,2,4-oxadiazol), wherein said heteroaryl                    is optionally substituted with halo (e.g., fluoro)                    or haloC₁₋₆alkyl;                -   amino (e.g., —NH₂),                -   C₁₋₆alkoxy,                -   —O-haloC₁₋₆alkyl (e.g., —O—CF₃),                -   C₁₋₆alkylsulfonyl (for example, methylsulfonyl or                    —S(O)₂CH₃),                -   —C(O)—R₁₃,                -   —N(R₁₄)(R₁₅); or        -   2) a substituted heteroarylaklyl, e.g., substituted with            haloalkyl; or        -   3) attached to one of the nitrogens on the pyrazolo portion            of Formula I and is a moiety of Formula A

-   -   -   -   wherein X, Y and Z are, independently, N or C, and R₈,                R₉, R₁₁ and R₁₂ are independently H or halogen (e.g., Cl                or F); and R₁₀ is halogen, alkyl, cycloalkyl, haloalkyl                (e.g., trifluoromethyl), aryl (e.g., phenyl), heteroaryl                (e.g., pyridyl, (for example, pyrid-2-yl) or e.g.,                thiadiazolyl (for example, 1,2,3-thiadiazol-4-yl),                diazolyl, triazolyl (e.g., 1,2,4-triazol-1-yl),                tetrazolyl (e.g., tetrazol-5-yl), alkoxadiazolyl (e.g.,                5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g.,                pyrazol-1-yl), alkyl sulfonyl (e.g., methyl sulfonyl),                arylcarbonyl (e.g., benzoyl), or heteroarylcarbonyl,                alkoxycarbonyl, (e.g., methoxycarbonyl), aminocarbonyl;                preferably phenyl or pyridyl, e.g., 2-pyridyl; provided                that when X, Y or X is nitrogen, R₈, R₉ or R₁₀,                respectively, is not present;

    -   (v) R₄ is selected from:        -   H,        -   C₁₋₆alkyl (e.g., methyl, isopropyl),        -   C₃₋₈cycloalkyl (e.g., cyclopentyl),        -   C₃₋₈heterocycloalkyl (e.g., pyrrolidin-3-yl),        -   aryl (e.g., phenyl) or heteroaryl (e.g., pyrid-4-yl,            pyrid-2-yl or pyrazol-3-yl) wherein said aryl or heteroaryl            is optionally substituted with halo (e.g., 4-fluorophenyl),            hydroxy (e.g., 4-hydroxyphenyl), C₁₋₆alkyl, C₁₋₆alkoxy or            another aryl group (e.g., biphenyl-4-ylmethyl);

    -   (vi) R₁₃ is —N(R₁₄)(R₁₅), C₁₋₆alkyl (e.g., methyl), —OC₁₋₆alkyl        (e.g., —OCH₃), haloC₁₋₆alkyl(trifluoromethyl), aryl (e.g.,        phenyl), or heteroaryl; and

    -   (vii) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl, in free or        salt form.

The invention further provides compounds of Formula I as follows:

-   -   1.1 Formula I, wherein R₃ is -D-E-F;    -   1.2 Formula 1.1, D is a single bond, C₁₋₆alkylene (e.g.,        methylene), or arylalkylene (e.g., benzylene or —CH₂C₆H₄—);    -   1.3 Formula 1.1, wherein D is a single bond;    -   1.4 Formula 1.1, wherein D is C₁₋₆alkylene (e.g., methylene);    -   1.5 Formula 1.1, wherein D is methylene;    -   1.6 Formula 1.1, wherein D is arylalkylene (e.g., benzylene or        —CH₂C₆H₄—);    -   1.7 Formula 1.1, wherein D is benzylene or —CH₂C₆H₄—;    -   1.8 Any of formulae 1.1-1.7, wherein E is a single bond,        C₂₋₄alkylene (e.g., methylene, ethynylene, prop-2-yn-1-ylene),        —C₀₋₄alkylarylene (e.g., phenylene or —C₆H₄—, -benzylene- or        —CH₂C₆H₄—), wherein the arylene group is optionally substituted        with halo (e.g., Cl or F), heteroarylene (e.g., pyridinylene or        pyrimidinylene), aminoC₁₋₆alkylene (e.g., —CH₂N(H)—), amino        (e.g., —N(H)—); C₃₋₈cycloalkylene optionally containing one or        more heteroatom selected from N or O (e.g., piperidinylene);    -   1.9 Any of formulae 1.1-1.7, wherein E is a single bond;    -   1.10 Any of formulae 1.1-1.7, wherein E is C₂₋₄alkylene (e.g.,        methylene, ethynylene, prop-2-yn-1-ylene);    -   1.11 Any of formulae 1.1-1.7, wherein E is methylene;    -   1.12 Any of formulae 1.1-1.7, wherein E is ethynylene;    -   1.13 Any of formulae 1.1-1.7, wherein E is prop-2-yn-1-ylene;    -   1.14 Any of formulae 1.1-1.7, wherein E is —C₀₋₄alkylarylene        (e.g., phenylene or —C₆₋H₄—, -benzylene- or —CH₂C₆H₄—), wherein        the arylene group is optionally substituted with halo (e.g., Cl        or F);    -   1.15 Any of formulae 1.1-1.7, wherein E is phenylene or —C₆H₄—;    -   1.16 Any of formulae 1.1-1.7, wherein E is heteroarylene (e.g.,        pyridinylene or pyrimidinylene);    -   1.17 Any of formulae 1.1-1.7, wherein E is pyridinylene;    -   1.18 Any of formulae 1.1-1.7, wherein E is pyrimidinylene;    -   1.19 Any of formulae 1.1-1.7, wherein E is aminoC₁₋₆alkylene        (e.g., —CH₂N(H)—);    -   1.20 Any of formulae 1.1-1.7, wherein E is amino (e.g., —N(H)—);    -   1.21 Any of formulae 1.1-1.7, wherein E is C₃₋₈cycloalkylene        optionally containing one or more heteroatom selected from N or        O (e.g., piperidinylene);    -   1.22 Any of formulae 1.1-1.21, wherein F is H, halo (e.g., F,        Br, Cl), C₁₋₆alkyl (e.g., isopropyl or isobutyl), haloC₁₋₆alkyl        (e.g., trifluoromethyl), aryl (e.g., phenyl), C₃₋₈cycloalkyl        optionally containing at least one atom selected from a group        consisting of N or O (e.g., cyclopentyl, cyclohexyl,        piperidinyl, pyrrolidinyl, tetrahydro-2H-pyran-4-yl, or        morpholinyl), and optionally substituted with C₁₋₆alkyl (e.g.,        methyl or isopropyl), for example, 1-methylpyrrolidin-2-yl,        pyrrolidin-1-yl, pyrrolidin-2-yl, piperidin-2-yl,        1-methylpiperidin-2-yl, 1-ethylpiperidin-2-yl; heteroaryl        optionally substituted with C₁₋₆alkyl (e.g., pyridyl, (for        example, pyrid-2-yl), pyrimidinyl (for example, pyrimidin-2-yl,        pyrimidin-4-yl), thiadiazolyl (for example,        1,2,3-thiadiazol-4-yl), oxazolyl (e.g., oxazol-2-yl), diazolyl        (e.g., pyrazolyl (for example, pyrazol-1-yl) or imidazolyl (for        example, imidazol-1-yl, 4-methylimidazolyl,        1-methylimidazol-2-yl,), triazolyl (e.g., 1,2,4-triazol-1-yl),        tetrazolyl (e.g., tetrazol-5-yl), alkoxadiazolyl (e.g.,        5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g., pyrazol-1-yl), amino        (e.g., —NH₂), C₁₋₆alkoxy, —O-haloC₁₋₆alkyl (e.g., —O—CF₃),        C₁₋₆alkylsulfonyl (for example, methylsulfonyl or —S(O)₂CH₃),        C(O)—R₁₃ or —N(R₁₄)(R₁₅);    -   1.23 Any of formulae 1.1-1.22, wherein F is H,    -   1.24 Any of formulae 1.1-1.22, wherein F is halo (e.g., F, Br,        Cl);    -   1.25 Any of formulae 1.1-1.22, wherein F is fluoro;    -   1.26 Any of formulae 1.1-1.22, wherein F is C₁₋₆alkyl (e.g.,        isopropyl or isobutyl);    -   1.27 Any of formulae 1.1-1.22, wherein F is isopropyl;    -   1.28 Any of formulae 1.1-1.22, wherein F is isobutyl;    -   1.29 Any of formulae 1.1-1.22, wherein F is haloC₁₋₆alkyl (e.g.,        trifluoromethyl);    -   1.30 Any of formulae 1.1-1.22, wherein F is trifluoromethyl;    -   1.31 Any of formulae 1.1-1.22, wherein F is aryl (e.g., phenyl);    -   1.32 Any of formulae 1.1-1.22, wherein F is phenyl;    -   1.33 Any of formulae 1.1-1.22, wherein F is C₃₋₈cycloalkyl        optionally containing at least one atom selected from a group        consisting of N or O (e.g., cyclopentyl, cyclohexyl,        piperidinyl, pyrrolidinyl tetrahydro-2H-pyran-4-yl,        morpholinyl); and optionally substituted with C₁₋₆alkyl (e.g.,        methyl or isopropyl), for example, 1-methylpyrrolidin-2-yl,),        for example, 1-methylpyrrolidin-2-yl, pyrrolidin-1-yl,        pyrrolidin-2-yl, piperidin-2-yl, 1-methylpiperidin-2-yl,        1-ethylpiperidin-2-yl;    -   1.34 Any of formulae 1.1-1.22, wherein F is cyclopentyl or        cyclohexyl;    -   1.35 Any of formulae 1.1-1.22, wherein F is        1-methylpyrrolidin-2-yl;    -   1.36 Any of formulae 1.1-1.22, wherein F is heteroaryl        optionally substituted with C₁₋₆alkyl (e.g., pyridyl, (for        example, pyrid-2-yl), pyrimidinyl (for example, pyrimidin-2-yl,        pyrimidin-4-yl), thiadiazolyl (for example,        1,2,3-thiadiazol-4-yl), oxazolyl (e.g., oxazol-2-yl), diazolyl        (e.g., pyrazolyl (for example, pyrazol-1-yl) or imidazolyl (for        example, imidazol-1-yl, 4-methylimidazolyl,        1-methylimidazol-2-yl,), triazolyl (e.g., 1,2,4-triazol-1-yl),        tetrazolyl (e.g., tetrazol-5-yl), alkoxadiazolyl (e.g.,        5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g., pyrazol-1-yl),        wherein said heteroaryl is optionally substituted with halo        (e.g., fluoro) or haloC₁₋₆alkyl;    -   1.37 Any of formulae 1.1-1.22, wherein F is pyrid-2-yl        optionally substituted with halo (e.g., fluoro);    -   1.38 Any of formulae 1.1-1.22, wherein F is 6-fluoro-pyrid-2-yl;    -   1.39 Any of formulae 1.1-1.22, wherein F is pyrimidinyl (for        example, pyrimidin-2-yl, pyrimidin-4-yl);    -   1.40 Any of formulae 1.1-1.22, wherein F is oxazolyl (e.g.,        oxazol-2-yl),    -   1.41 Any of formulae 1.1-1.22, wherein F is triazolyl (e.g.,        1,2,4-triazol-1-yl);    -   1.42 Any of formulae 1.1-1.22, wherein F is diazolyl (e.g.,        pyrazolyl (for example, pyrazol-1-yl) or imidazolyl (for        example, imidazol-1-yl, 4-methylimidazolyl,        1-methylimidazol-2-yl,);    -   1.43 Any of formulae 1.1-1.22, wherein F is        C₁₋₆alkyl-oxadiazolyl (e.g., 5-methyl-1,2,4-oxadiazolyl);    -   1.44 Any of formulae 1.1-1.22, wherein F is amino (e.g., —NH₂);    -   1.45 Any of formulae 1.1-1.22, wherein F is C₁₋₆alkoxy;    -   1.46 Any of formulae 1.1-1.22, wherein F is —O-haloC₁₋₆alkyl        (e.g., —O—CF₃);    -   1.47 Any of formulae 1.1-1.22, wherein F is —C(O)—R₁₃;    -   1.48 Any of formulae 1.1-1.22, wherein F is —N(R₁₄)(R₁₅);    -   1.49 Any of formulae 1.1-1.22, wherein F is C₁₋₆alkylsulfonyl;    -   1.50 Any of formulae 1.1-1.22, wherein F is methylsulfonyl or        —S(O)₂CH₃;    -   1.51 Formula I or any of 1.1-1.21, wherein R₃ is a substituted        heteroarylaklyl, e.g., substituted with haloalkyl;    -   1.52 Formula I or any of 1.1-1.21, wherein R₃ is attached to one        of the nitrogens on the pyrazolo portion of Formula I and is a        moiety of Formula A

-   -   -   wherein X, Y and Z are, independently, N or C, and R₈, R₉,            R₁₁ and R₁₂ are independently H or halogen (e.g., Cl or F);            and R₁₀ is halogen, alkyl, cycloalkyl, haloalkyl (e.g.,            trifluoromethyl), aryl (e.g., phenyl), heteroaryl (e.g.,            pyridyl, (for example, pyrid-2-yl) or e.g., thiadiazolyl            (for example, 1,2,3-thiadiazol-4-yl), diazolyl, triazolyl            (e.g., 1,2,4-triazol-1-yl), tetrazolyl (e.g.,            tetrazol-5-yl), alkoxadiazolyl (e.g.,            5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g., pyrazol-1-yl),            alkyl sulfonyl (e.g., methyl sulfonyl), arylcarbonyl (e.g.,            benzoyl), or heteroarylcarbonyl, alkoxycarbonyl, (e.g.,            methoxycarbonyl), aminocarbonyl; preferably phenyl or            pyridyl, e.g., 2-pyridyl; provided that when X, Y or X is            nitrogen, R₈, R₉ or R₁₀, respectively, is not present;

    -   1.53 Formula 1.52, wherein R₃ is a moiety of Formula A, R₈, R₉,        R₁₁ and R₁₂ are each H and R₁₀ is phenyl;

    -   1.54 Formula 1.52, wherein R₃ is a moiety of Formula A, R₈, R₉,        R₁₁ and R₁₂ are each H and R₁₀ is pyridyl or thiadiazolyl;

    -   1.55 Formula 1.52, wherein R₃ is a moiety of Formula A, R₈, R₉,        R₁₁ and R₁₂ are each H and R₁₀ is pyrid-2-yl optionally        substituted with halo (e.g., fluoro);

    -   1.56 Formula 1.52, wherein R₃ is a moiety of Formula A and X, Y        and Z are all C,

    -   1.57 Formula 1.52, wherein R₁₀ is pyrimidinyl;

    -   1.58 Formula 1.52, wherein R₁₀ is 5-fluoropyrmidinyl;

    -   1.59 Formula 1.52, wherein R₁₀ is pyrazol-1-yl;

    -   1.60 Formula 1.52, wherein R₁₀ is 1,2,4-triazol-1-yl;

    -   1.61 Formula 1.52, wherein R₁₀ is aminocarbonyl;

    -   1.62 Formula 1.52, wherein R₁₀ is methylsulfonyl;

    -   1.63 Formula 1.52, wherein R₁₀ is 5-methyl-1,2,4-oxadiazol-3-yl;

    -   1.64 Formula 1.52, wherein R₁₀ is 5-fluoropyrimidin-2-yl;

    -   1.65 Formula 1.52, wherein R₁₀ is trifluoromethyl;

    -   1.66 Formula 1.52, wherein R₃ is a moiety of Formula A, X and Z        are C, and Y is N,

    -   1.67 Formula I or any of 1.1-1.66, wherein R₂ is H; C₁₋₆alkyl        (e.g., isopropyl, isobutyl, neopentyl, 2-methylbutyl,        2,2-dimethylpropyl) wherein said alkyl group is optionally        substituted with halo (e.g., fluoro) or hydroxy (e.g.,        1-hydroxypropan-2-yl, 3-hydroxy-2-methylpropyl);        —C₀₋₄alkyl-C₃₋₈cycloalkyl (e.g., cyclopentyl, cyclohexyl)        optionally substituted with one or more amino (e.g., —NH₂), for        example, 2-aminocyclopentyl or 2-aminocyclohexyl), wherein said        cycloalkyl optionally contains one or more heteroatom selected        from N and O and is optionally substituted with C₁₋₆alkyl (e.g.,        1-methyl-pyrrolindin-2-yl, 1-methyl-pyrrolindin-3-yl,        1-methyl-pyrrolindin-2-yl-methyl or        1-methyl-pyrrolindin-3-yl-methyl); C₃₋₈heterocycloalkyl (e.g.,        pyrrolidinyl, for example, pyrrolidin-3-yl) optionally        substituted with C₁₋₆alkyl (e.g., methyl), for example,        1-methylpyrrolidin-3-yl; C₃₋₈cycloalkyl-C₁₋₆alkyl (e.g.,        cyclopropylmethyl); haloC₁₋₆alkyl (e.g., trifluoromethyl,        2,2,2-trifluoroethyl); —N(R₁₄)(R₁₅)—C₁₋₆alkyl (e.g.,        2-(dimethylamino)ethyl,2-aminopropyl); hydroxyC₁₋₆alkyl (e.g.,        (e.g., 3-hydroxy-2-methylpropyl, 1-hydroxyprop-2-yl);        arylC₀₋₆alkyl (e.g., benzyl); heteroarylC₁₋₆alkyl (e.g.,        pyridinylmethyl); C₁₋₆alkoxyarylC₁₋₆alkyl (e.g.,        4-methoxybenzyl); -G-J wherein: G is a single bond or, alkylene        (e.g., methylene) and J is cycloalkyl or heterocycloalkyl (e.g.,        oxetan-2-yl, pyrolyin-3-yl, pyrolyin-2-yl) optionally        substituted with C₁₋₆alkyl (e.g., (1-methylpyrrolidin-2-yl));

    -   1.68 Formula 1.66, wherein R₂ is H,

    -   1.69 Formula 1.66, wherein R₂ is C₁₋₆alkyl (e.g., isopropyl,        isobutyl, neopentyl, 2-methylbutyl, 2,2-dimethylpropyl) wherein        said alkyl group is optionally substituted with halo (e.g.,        trifluoroethyl) or hydroxy (e.g., 1-hydroxypropan-2-yl,        3-hydroxy-2-methylpropyl);

    -   1.70 Formula 1.66, wherein R₂ is isobutyl;

    -   1.71 Formula 1.66, wherein R₂ is 3-hydroxy-2-methylpropyl;

    -   1.72 Formula 1.66, wherein R₂ is 1-hydroxypropan-2-yl;

    -   1.73 Formula 1.66, wherein R₂ is —C₀₋₄alkyl-C₃₋₈cycloalkyl        (e.g., cyclopentyl, cyclohexyl) optionally substituted with one        or more amino (e.g., —NH₂), for example, 2-aminocyclopentyl or        2-aminocyclohexyl), wherein said cycloalkyl optionally contains        one or more heteroatom selected from N and O and is optionally        substituted with C₁₋₆alkyl (e.g., 1-methyl-pyrrolindin-2-yl,        1-methyl-pyrrolindin-3-yl, 1-methyl-pyrrolindin-2-yl-methyl or        1-methyl-pyrrolindin-3-yl-methyl);

    -   1.74 Formula 1.66, wherein R₂ is 1-methyl-pyrrolindin-2-yl,        1-methyl-pyrrolindin-3-yl, 1-methyl-pyrrolindin-2-yl-methyl or        1-methyl-pyrrolindin-3-yl-methyl;

    -   1.75 Formula 1.66, wherein R₂ is C₃₋₈heterocycloalkyl (e.g.,        pyrrolidinyl, for example, pyrrolidin-3-yl) optionally        substituted with C₁₋₆alkyl (e.g., methyl), for example,        1-methylpyrrolidin-3-yl;

    -   1.76 Formula 1.66, wherein R₂ is 1-methylpyrrolidin-3-yl;

    -   1.77 Formula 1.66, wherein R₂ is C₃₋₈cycloalkyl-C₁₋₆alkyl (e.g.,        cyclopropylmethyl);

    -   1.78 Formula 1.66, wherein R₂ is —N(R₁₄)(R₁₅)—C₁₋₆alkyl (e.g.,        2-(dimethylamino)ethyl, 2-aminopropyl);

    -   1.79 Formula 1.66, wherein R₂ is heteroarylC₁₋₆alkyl (e.g.,        pyridinylmethyl),

    -   1.80 Formula 1.66, wherein R₂ is C₁₋₆alkoxyarylC₁₋₆alkyl (e.g.,        4-methoxybenzyl;

    -   1.81 Formula 1.66, wherein R₂ is arylC₀₋₆alkyl (e.g., benzyl);

    -   1.82 Formula 1.66, wherein R₂ is cyclopentyl or cyclohexyl;

    -   1.83 Formula I or any of 1.1-1.66, wherein R₂ is -G-J; G is a        single bond or, alkylene (e.g., methylene); and J is cycloalkyl        or heterocycloalkyl (e.g., oxetan-2-yl, pyrolyin-3-yl,        pyrolyin-2-yl) optionally substituted with C₁₋₆alkyl (e.g.,        (1-methylpyrrolidin-2-yl));

    -   1.84 Formula 1.83, wherein G is alkylene (e.g., methylene);

    -   1.85 Formula 1.83, wherein G is methylene;

    -   1.86 Formula 1.83, wherein J is cycloalkyl or heterocycloalkyl        (e.g., oxetan-2-yl, pyrolyin-3-yl, pyrolyin-2-yl) optionally        substituted with alkyl (e.g., 1-methylpyrrolidin-2-yl);

    -   1.87 Formula 1.83, wherein J is oxetan-2-yl, pyrolyin-3-yl,        pyrolyin-2-yl;

    -   1.88 Formula 1.83, wherein J is (1-methylpyrrolidin-2-yl);

    -   1.89 Any of the preceding formulae wherein R₄ is selected from        H, C₁₋₆alkyl (e.g., methyl, isopropyl), C₃₋₈cycloalkyl (e.g.,        cyclopentyl), C₃₋₈heterocycloalkyl (e.g., pyrrolidin-3-yl), or        aryl (e.g., phenyl) or heteroaryl (e.g., pyrid-4-yl, pyrid-2-yl        or pyrazol-3-yl) wherein said aryl or heteroaryl is optionally        substituted with halo (e.g., 4-fluorophenyl), hydroxy (e.g.,        4-hydroxyphenyl), C₁₋₆alkoxy C₁₋₆alkyl, or C₁₋₆alkoxy or another        aryl group (e.g., biphenyl-4-ylmethyl);

    -   1.90 Formula 1.89, wherein either R₄ is H,

    -   1.91 Formula 1.89, wherein either R₄ or R₅ is C₁₋₆alkyl (e.g.,        methyl, isopropyl);

    -   1.92 Formula 1.89, wherein either R₄ is isopropyl;

    -   1.93 Formula 1.89, wherein either R₄ or R₅ is C₃₋₈cycloalkyl        (e.g., cyclopentyl);

    -   1.94 Formula 1.89, wherein either R₄ or R₅ is        C₃₋₈heterocycloalkyl (e.g., pyrrolidin-3-yl);

    -   1.95 Formula 1.89, wherein either R₄ or R₅ is aryl (e.g.,        phenyl) optionally substituted with halo (e.g., 4-fluorophenyl),        hydroxy (e.g., 4-hydroxyphenyl), C₁₋₆alkyl, C₁₋₆alkoxy or        another aryl group (e.g., biphenyl-4-ylmethyl);

    -   1.96 Formula 1.89, wherein either R₄ or R₅ is 4-hydroxyphenyl;

    -   1.97 Formula 1.89, wherein either R₄ or R₅ is 4-fluorophenyl;

    -   1.98 Formula 1.89, wherein either R₄ or R₅ is heteroaryl (e.g.,        pyrid-4-yl, pyrid-2-yl or pyrazol-3-yl) optionally substituted        with halo (e.g., 4-fluorophenyl), hydroxy (e.g.,        4-hydroxyphenyl), C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group        (e.g., biphenyl-4-ylmethyl);

    -   1.99 Formula 1.89, wherein either R₄ or R₅ is phenyl;

    -   1.100 Any of the foregoing formulae, wherein R¹³ is        —N(R₁₄)(R₁₅), C₁₋₆alkyl (e.g., methyl), —OC₁₋₆alkyl (e.g.,        —OCH₃), haloC₁₋₆alkyl, aryl (for example phenyl), or heteroaryl;

    -   1.101 Formula 1.100, wherein R¹³ is —N(R₁₄)(R₁₅);

    -   1.102 Formula 1.100, wherein R¹³ is —NH₂;

    -   1.103 Formula 1.100, wherein R¹³ is C₁₋₆alkyl (e.g., methyl);

    -   1.104 Formula 1.100, wherein R¹³ is —OC₁₋₆alkyl (e.g., —OCH₃),

    -   1.105 Formula 1.100, wherein R¹³ is —OCH₃;

    -   1.106 Formula 1.100, wherein R¹³ is haloC₁₋₆alkyl (e.g.,        trifluoromethyl);

    -   1.107 Formula 1.100, wherein R¹³ is trifluoromethyl;

    -   1.108 Formula 1.100, wherein R¹³ is aryl (e.g., phenyl);

    -   1.109 Formula 1.100, wherein R¹³ is heteroaryl (e.g., pyridyl);

    -   1.110 Any of the preceding formulae, wherein R₁₄ and R₁₅ are        independently H or C₁₋₆alkyl (e.g., methyl);

    -   1.111 Formula I or any of 1.1-1.110, wherein either R₁₄ or R₁₅        is independently H,

    -   1.112 Formula I or any of 1.1-1.110, wherein either R₁₄ or R₁₅        is C₁₋₆alkyl (e.g., methyl);

    -   1.113 Formula I or any of 1.1-1.110, wherein either R₁₄ or R₁₅        is methyl;

    -   1.114 Formula I or any of 1.1-1.110, wherein R₁₄ and R₁₅ are        methyl;

    -   1.115 any of the preceding formulae wherein R₃ is selected from        a group consisting of 4-(pyrimidin-2-yl)benzyl,        4-(1,2,4-triazol-1-yl)benzyl, 4-(1-methylpyrrolidin-2-yl)benzyl,        4-(1-methylpiperid-2-yl)benzyl, 4-(pyrid-2-yl)benzyl,        4-(pyrazol-1-yl)benzyl, 4-(pyrrolidin-3-yl)benzyl,        (6-chloropyridin-3-yl)methyl, (6-fluoropyridin-3-yl)methyl,        4-(imidazol-1-yl)benzyl, 4-(pyrimidin-4-yl)benzyl),        4-(oxazol-2-yl)benzyl, 4-(dimethylamino)benzyl,        4-(methylsulfonyl)benzyl, 4-(pyrrolidin-3-yl)benzyl,        (1-isopropylpyiperidin-4-yl)methyl, and —CH₂—C₂H₄—C(O)—NH₂;

    -   1.116 formula 1.115 wherein R₃ is 4-(pyrimidin-2-yl)benzyl;

    -   1.117 formula 1.115 wherein R₃ is 4-(1,2,4-triazol-1-yl)benzyl;

    -   1.118 formula 1.115 wherein R₃ is        4-(1-methylpyrrolidin-2-yl)benzyl;

    -   1.119 formula 1.115 wherein R₃ is        4-(1-methylpiperid-2-yl)benzyl;

    -   1.120 formula 1.115 wherein R₃ is 4-(pyrid-2-yl)benzyl;

    -   1.121 formula 1.115 wherein R₃ is 4-(pyrazol-1-yl)benzyl;

    -   1.122 formula 1.115 wherein R₃ is 4-(pyrrolidin-3-yl)benzyl;

    -   1.123 formula 1.115 wherein R₃ is (6-chloropyridin-3-yl)methyl        or (6-fluoropyridin-3-yl)methyl;

    -   1.124 formula 1.115 wherein R₃ is 4-(imidazol-1-yl)benzyl;

    -   1.125 formula 1.115 wherein R₃ is 4-(pyrimidin-4-yl)benzyl);

    -   1.126 formula 1.115 wherein R₃ is 4-(oxazol-2-yl)benzyl;

    -   1.127 formula 1.115 wherein R₃ is 4-(dimethylamino)benzyl;

    -   1.128 formula 1.115 wherein R₃ is 4-(methylsulfonyl)benzyl;

    -   1.129 formula 1.115 wherein R₃ is 4-(pyrrolidin-3-yl)benzyl;

    -   1.130 formula 1.115 wherein R₃ is        (1-isopropylpyiperidin-4-yl)methyl;

    -   1.131 formula 1.115 wherein R₃ is —CH₂—C₂H₄—C(O)—NH₂;

    -   1.132 any of the preceding formulae wherein compound of formula        I is

-   -   1.133 any of the preceding formulae wherein compound of formula        I is

-   -   1.134 any of the preceding formulae wherein compound of formula        I is selected from a group consisting of:

-   -   1.135 any of the preceding formulae wherein the compounds        inhibit phosphodiesterase-mediated (e.g., PDE1-mediated,        especially PDE1B-mediated) hydrolysis of cGMP, e.g., with an        IC₅₀ of less than 10 μM, preferably less than 1 μM, preferably        less than 500 nM, preferably less than 200 nM in an        immobilized-metal affinity particle reagent PDE assay, for        example, as described in Example 16, in free or salt form.

In a further embodiment, the Compound of the Invention is a Compound ofFormula I, wherein R₃ is C₅₋₆heteroarylC₁₋alkyl optionally substitutedwith halo, C1-6alkyl (e.g., (6-fluoropyrid-3-yl)methyl,(6-chloropyrid-3-yl)methyl).

In another embodiment, the Compound of the Invention is a Compound ofFormula I, wherein R₃ is pyridylC₁₋₆alkyl (e.g., pyridylmethyl)optionally substituted with halo, haloalkyl alkyl sulfonyl,—C(O)N(C₀₋₆alkyl)(C₀₋₆alkyl), heteroaryl (e.g., pyridyl, pyrimidinyl,oxazole, imidazole, triazolyl, pyrazolyl), amino, C₁₋₆alkylamino, andheterocycloalkyl (e.g., piperidinyl, pyrrolidinyl) whichheterocycloalkyl, heteroaryl are further optionally substituted withC₁₋₆alkyl or halo.

In still another embodiment, the Compound of the Invention is a Compoundof Formula I, wherein R₃ is benzyl substituted with aryl, heteroaryl(e.g., pyridyl, pyrimidinyl, oxazole, imidazole, triazolyl, pyrazolyl),C₃₋₇cycloalkyl, heteroC₃₋₇cycloalkyl (e.g., piperidinyl, pyrrolidinyl),alkyl sulfonyl, —C(O)N(C₀₋₆alkyl)(C₀₋₆ alkyl), amino, C₁₋₆alkylamino,which aryl, heterocycloalkyl, heteroaryl are further optionallysubstituted with C₁₋₆alkyl or halo.

In a another embodiment, the Compound of the Invention is a Compound ofFormula I wherein

-   -   (ii) R₁ is H or alkyl (e.g., methyl);    -   (iii) R₂ is H, alkyl (e.g., isobutyl, 2-methylbutyl,        2,2-dimethyl propyl), cycloalkyl (e.g., cyclopentyl,        cyclohexyl), haloalkyl (e.g., trifluoromethyl,        2,2,2-trifluoroethyl), alkylaminoalkyl (e.g.,        2-(dimethylamino)ethyl), hydroxyalkyl (e.g., 3-hydroxy-2-methyl        propyl), arylalkyl (e.g., benzyl), heteroarylalkyl (e.g.,        pyridylmethyl), or alkoxyarylalkyl (e.g., 4-methoxybenzyl);    -   (iv) R₃ is a substituted heteroarylaklyl, e.g., substituted with        haloalkyl    -   or    -   R₃ is attached to one of the nitrogens on the pyrazolo portion        of Formula I and is    -   a moiety of Formula A

wherein X, Y and Z are, independently, N or C, and R₈, R₉, R₁₁ and R₁₂are independently H or halogen (e.g., Cl or F); and R₁₀ is halogen,alkyl, cycloalkyl, haloalkyl (e.g., trifluoromethyl), aryl (e.g.,phenyl), heteroaryl (e.g., pyridyl, (for example, pyrid-2-yl) or e.g.,thiadiazolyl (for example, 1,2,3-thiadiazol-4-yl), diazolyl, triazolyl(e.g., 1,2,4-triazol-1-yl), tetrazolyl (e.g., tetrazol-5-yl),alkoxadiazolyl (e.g., 5-methyl-1,2,4-oxadiazol), pyrazolyl (e.g.,pyrazol-1-yl), alkyl sulfonyl (e.g., methyl sulfonyl), arylcarbonyl(e.g., benzoyl), or heteroarylcarbonyl, alkoxycarbonyl, (e.g.,methoxycarbonyl), aminocarbonyl; preferably phenyl or pyridyl, e.g.,2-pyridyl; provided that when X, Y or X is nitrogen, R₈, R₉ or R₁₀,respectively, is not present;

-   -   (v) R₄ is aryl (e.g., phenyl) or heteroaryl;    -   (vi) R₅ is H, alkyl, cycloalkyl (e.g., cyclopentyl), heteroaryl,        aryl, p-benzylaryl (e.g., biphenyl-4-ylmethyl);    -   (vii) R₆ is H, C₁₋₆alkyl (e.g., methyl) or C₃₋₈cycloalkyl;    -   (viii) R₁₃ is —N(R₁₄)(R₁₅), C₁₋₆alkyl (e.g., methyl),        —OC₁₋₆alkyl (e.g., —OCH₃), haloC₁₋₆alkyl(trifluoromethyl), aryl        (e.g., phenyl), or heteroaryl; and    -   (vii) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl,        in free or salt form (hereinafter, Compound of Formula I(i)).

In still another embodiment, the Compound of the Invention is a Compoundof Formula I wherein

-   -   (i) R₁ is H or alkyl (e.g., methyl);    -   (ii) R₂ is H, alkyl (e.g., isopropyl, isobutyl, 2-methylbutyl,        2,2-dimethyl propyl), cycloalkyl (e.g., cyclopentyl,        cyclohexyl), haloalkyl (e.g., trifluoromethyl,        2,2,2-trifluoroethyl), alkylaminoalkyl (e.g.,        2-(dimethylamino)ethyl), hydroxyalkyl (e.g., 3-hydroxy-2-methyl        propyl), arylalkyl (e.g., benzyl), heteroarylalkyl (e.g.,        pyridylmethyl), or alkoxyarylalkyl (e.g., 4-methoxybenzyl);    -   (iii) R₃ is D-E-F wherein        -   1. D is single bond, alkylene (e.g., methylene), or            arylalkylene (e.g., benzylene or —CH₂C₆H₄—);        -   2. E is a alkylene (e.g., methylene, ethynylene,            prop-2-yn-1-ylene), arylene (e.g., phenylene or —C₆H₄—),            alkylarylene (e.g., -benzylene- or —CH₂C₆H₄—), aminoalkylene            (e.g., —CH₂N(H)—) or amino (e.g., —N(H)—); and        -   3. F is alkyl (e.g., isobutyl), aryl (e.g., phenyl),            heteroaryl (e.g., pyrid-2-yl, 1,2,4-triazolyl),            heteroC₃₋₈cycloalkyl (e.g., pyrrolidin-1-yl), amino (e.g.,            —NH₂), C₁₋₆alkoxy, or —O-haloalkyl (e.g., —O—CF₃);    -   (iv) R₄ is aryl (e.g., phenyl), heteroaryl (e.g., pyrid-4-yl,        pyrid-2-yl or pyrazol-3-yl) or heterocycloalkyl (e.g.,        pyrrolidin-3-yl); and    -   (v) R₅ is H, alkyl, cycloalkyl (e.g., cyclopentyl), heteroaryl,        aryl, p-benzylaryl (e.g., biphenyl-4-ylmethyl);    -   (vi) R₆ is H, C₁₋₆alkyl (e.g., methyl) or C₃₋₈cycloalkyl;    -   (vii) R₁₃ is —N(R₁₄)(R₁₅), C₁₋₆alkyl (e.g., methyl), —OC₁₋₆alkyl        (e.g., —OCH₃), haloC₁₋₆alkyl(trifluoromethyl), aryl (e.g.,        phenyl), or heteroaryl; and    -   (viii) R₁₄ and R₁₅ are independently H or alkyl,        wherein “alk”, “alkyl”, “haloalkyl” or “alkoxy” refers to C₁₋₆        alkyl and “cycloalkyl” refers to C₃₋₈ cycloalkyl unless        specifically specified;        in free or salt form (hereinafter, Compound of Formula I(ii)).

If not otherwise specified or clear from context, the following termsherein have the following meanings:

-   -   (a) “Alkyl” as used herein is a saturated or unsaturated        hydrocarbon moiety, preferably saturated, preferably having one        to six carbon atoms, which may be linear or branched, and may be        optionally mono-, di- or tri-substituted, e.g., with halogen        (e.g., chloro or fluoro), hydroxy, or carboxy.    -   (b) “Cycloalkyl” as used herein is a saturated or unsaturated        nonaromatic hydrocarbon moiety, preferably saturated, preferably        comprising three to eight carbon atoms, at least some of which        form a nonaromatic mono- or bicyclic, or bridged cyclic        structure, and which may be optionally substituted, e.g., with        halogen (e.g., chloro or fluoro), hydroxy, or carboxy. Wherein        the cycloalkyl optionally contains one or more atoms selected        from N and O and/or S, said cycloalkyl may also be a        heterocycloalkyl.    -   (c) “Heterocycloalkyl” is, unless otherwise indicated, saturated        or unsaturated nonaromatic hydrocarbon moiety, preferably        saturated, preferably comprising three to nine carbon atoms, at        least some of which form a nonaromatic mono- or bicyclic, or        bridged cyclic structure, wherein at least one carbon atom is        replaced with N, O or S, which heterocycloalkyl may be        optionally substituted, e.g., with halogen (e.g., chloro or        fluoro), hydroxy, or carboxy.    -   (d) “Aryl” as used herein is a mono or bicyclic aromatic        hydrocarbon, preferably phenyl, optionally substituted, e.g.,        with alkyl (e.g., methyl), halogen (e.g., chloro or fluoro),        haloalkyl (e.g., trifluoromethyl), hydroxy, carboxy, or an        additional aryl or heteroaryl (e.g., biphenyl or pyridylphenyl).    -   (e) “Heteroaryl” as used herein is an aromatic moiety wherein        one or more of the atoms making up the aromatic ring is sulfur        or nitrogen rather than carbon, e.g., pyridyl or thiadiazolyl,        which may be optionally substituted, e.g., with alkyl, halogen,        haloalkyl, hydroxy or carboxy.    -   (1) Wherein E is phenylene, the numbering is as follows:

-   -   (g) It is intended that wherein the substituents end in “ene”,        for example, alkylene, phenylene or arylalkylene, said        substitutents are intended to bridge or be connected to two        other substituents. Therefore, methylene is intended to be —CH₂—        and phenylene intended to be —C₆H₄— and arylalkylene is intended        to be —C₆H₄—CH₂— or —CH₂—C₆H₄—.

Compounds of the Invention may exist in free or salt form, e.g., as acidaddition salts. In this specification unless otherwise indicated,language such as “Compounds of the Invention” is to be understood asembracing the compounds of Formula I, or any of 1.1-1.135, a Compound ofFormula I(i) or I(ii), in any form, for example free or acid additionsalt form, or where the compounds contain acidic substituents, in baseaddition salt form. The Compounds of the Invention are intended for useas pharmaceuticals, therefore pharmaceutically acceptable salts arepreferred. Salts which are unsuitable for pharmaceutical uses may beuseful, for example, for the isolation or purification of free Compoundsof the Invention or their pharmaceutically acceptable salts, aretherefore also included.

Compounds of the Invention may in some cases also exist in prodrug form.A prodrug form is compound which converts in the body to a Compound ofthe Invention. For example, when the Compounds of the Invention containhydroxy or carboxy substituents, these substituents may formphysiologically hydrolysable and acceptable esters. As used herein,“physiologically hydrolysable and acceptable ester” means esters ofCompounds of the Invention which are hydrolysable under physiologicalconditions to yield acids (in the case of Compounds of the Inventionwhich have hydroxy substituents) or alcohols (in the case of Compoundsof the Invention which have carboxy substituents) which are themselvesphysiologically tolerable at doses to be administered. Therefore,wherein the Compound of the Invention contains a hydroxy group, forexample, Compound —OH, the acyl ester prodrug of such compound, i.e.,Compound —O—C(O)—C₁₋₄alkyl, can hydrolyze in the body to formphysiologically hydrolysable alcohol (Compound —OH) on the one hand andacid on the other (e.g., HOC(O)—C₁₋₄alkyl). Alternatively, wherein theCompound of the Invention contains a carboxylic acid, for example,Compound —C(O)OH, the acid ester prodrug of such compound, Compound—C(O)O—C₁₋₄alkyl can hydrolyze to form Compound —C(O)OH andHO—C₁₋₄alkyl. As will be appreciated, the term thus embracesconventional pharmaceutical prodrug forms.

The invention also provides methods of making the Compounds of theInvention and methods of using the Compounds of the Invention fortreatment of diseases and disorders as set forth below (especiallytreatment of diseases characterized by reduced dopamine D1 receptorsignaling activity, such as Parkinson's disease, Tourette's Syndrome,Autism, fragile X syndrome, ADHD, restless leg syndrome, depression,cognitive impairment of schizophrenia, narcolepsy and diseases that maybe alleviated by the enhancement of progesterone-signaling such asfemale sexual dysfunction), or a disease or disorder such as psychosisor glaucoma). This list is not intended to be exhaustive and may includeother diseases and disorders as set forth below.

In another embodiment, the invention further provides a pharmaceuticalcomposition comprising a Compound of the Invention, e.g., a Compound ofFormula I, or any of 1.1-1.135, or a Compound of Formula I(i) or I(ii),or any described in this specification, in free or pharmaceuticallyacceptable salt form, in admixture with a pharmaceutically acceptablecarrier.

DETAILED DESCRIPTION OF THE INVENTION Methods of Making Compounds of theInvention

The Compounds of the Invention and their pharmaceutically acceptablesalts may be made using the methods as described and exemplified hereinand by methods similar thereto and by methods known in the chemical art.Such methods include, but not limited to, those described below. If notcommercially available, starting materials for these processes may bemade by procedures, which are selected from the chemical art usingtechniques which are similar or analogous to the synthesis of knowncompounds. In particular, the intermediates and starting materials forthe Compounds of the Invention may be prepared by methods and processesas described in PCT/US2007/070551. All references cited herein arehereby incorporated by reference in their entirety.

The Compounds of the Invention include their enantiomers,diastereoisomers, tautomers and racemates, as well as their polymorphs,hydrates, solvates and complexes. Some individual compounds within thescope of this invention may contain double bonds. Representations ofdouble bonds in this invention are meant to include both the E and the Zisomer of the double bond. In addition, some compounds within the scopeof this invention may contain one or more asymmetric centers. Thisinvention includes the use of any of the optically pure stereoisomers aswell as any combination of stereoisomers.

It is also intended that the Compounds of the Invention encompass theirstable and unstable isotopes. Stable isotopes are nonradioactiveisotopes which contain one additional neutron compared to the abundantnuclides of the same species (i.e., element). It is expected that theactivity of compounds comprising such isotopes would be retained, andsuch compound would also have utility for measuring pharmacokinetics ofthe non-isotopic analogs. For example, the hydrogen atom at a certainposition on the Compounds of the Invention may be replaced withdeuterium (a stable isotope which is non-radioactive). Examples of knownstable isotopes include, but not limited to, deuterium, ¹³C, ¹⁵N, ¹⁸O.Alternatively, unstable isotopes, which are radioactive isotopes whichcontain additional neutrons compared to the abundant nuclides of thesame species (i.e., element), e.g., ¹²³I, ¹³¹I, ¹²⁵I, ¹¹C, ¹⁸F, mayreplace the corresponding abundant species of I, C and F. Anotherexample of useful isotope of the compound of the invention is the ¹¹Cisotope. These radio isotopes are useful for radio-imaging and/orpharmacokinetic studies of the compounds of the invention.

Melting points are uncorrected and (dec) indicates decomposition.Temperature are given in degrees Celsius (° C.); unless otherwisestated, operations are carried out at room or ambient temperature, thatis, at a temperature in the range of 18-25° C. Chromatography meansflash chromatography on silica gel; thin layer chromatography (TLC) iscarried out on silica gel plates. NMR data is in the delta values ofmajor diagnostic protons, given in parts per million (ppm) relative totetramethylsilane (TMS) as an internal standard. Conventionalabbreviations for signal shape are used. Coupling constants (J) aregiven in Hz. For mass spectra (MS), the lowest mass major ion isreported for molecules where isotope splitting results in multiple massspectral peaks Solvent mixture compositions are given as volumepercentages or volume ratios. In cases where the NMR spectra arecomplex, only diagnostic signals are reported.

Terms and Abbreviations:

BuLi=n-butyllithium

Bu^(t)OH=tert-butyl alcohol,

CAN=ammonium cerium (IV) nitrate,

DIPEA=diisopropylethylamine,

DMF=N,N-dimethylforamide,

DMSO=dimethyl sulfoxide,

Et₂O=diethyl ether,

EtOAc=ethyl acetate,

equiv.=equivalent(s),

h=hour(s),

HPLC=high performance liquid chromatography,

LDA=lithium diisopropylamide

MeOH=methanol,

NBS=N-bromosuccinimide

NCS=N-chlorosuccinimide

NaHCO₃=sodium bicarbonate,

NH₄OH=ammonium hydroxide,

Pd₂(dba)₃=tris[dibenzylideneacetone]dipalladium(0)

PMB=p-methoxybenzyl,

POCl₃=phosphorous oxychloride,

SOCl₂=thionyl chloride,

TFA=trifluoroacetic acid,

THF=tetrahedrofuran.

The synthetic methods in this invention are illustrated below. Thesignificances for the R groups are as set forth above for formula Iunless otherwise indicated.

In an aspect of the invention, intermediate compounds of formula IIb canbe synthesized by reacting a compound of formula IIa with a dicarboxylicacid, acetic anhydride and acetic acid mixing with heat for about 3hours and then cooled:

wherein R₁ is H or C₁₋₄alkyl [e.g., methyl].

Intermediate IIc can be prepared by for example reacting a compound ofIIb with for example a chlorinating compound such as POCl₃, sometimeswith small amounts of water and heated for about 4 hours and thencooled:

Intermediate IId may be formed by reacting a compound of IIc with forexample a P¹—X in a solvent such as DMF and a base such as K₂CO₃ at roomtemperature or with heating:

wherein P¹ is a protective group [e.g., p-methoxybenzyl group (PMB)]; Xis a leaving group such as a halogen, mesylate, or tosylate.

Intermediate IIe may be prepared by reacting a compound of IId withhydrazine or hydrazine hydrate in a solvent such as methanol andrefluxed for about 4 hours and then cooled:

Alternatively, Intermediate IIIa may be formed by reacting a compound ofIIc with for example a R₂—X wherein X is a leaving group such as ahalogen, mesylate, or tosylate, in a solvent such as DMF and a base suchas K₂CO₃ at room temperature or with heating:

Intermediate IIIb may be prepared by reacting a compound of IIIa withhydrazine or hydrazine hydrate in a solvent such as methanol and heatedfor several hours and then cooled:

Intermediate IVa may be formed by for example reacting a compound ofIIIb with POCl₃ and DMF.

Intermediate IVb may be formed by reacting a compound of IVa with forexample a R₃—X wherein X here is a leaving group, e.g., halogen,mesylate, or tosylate, in a solvent such as DMF and a base such as K₂CO₃at room temperature or with heating.

The thio Compounds of the Invention, e.g., Formula I wherein L is S orCompound (I)-E may be prepared by reacting a compound (IVb) with adisulfide R₄-L-L-R₄ or a thiol R₄-LH in the presence of a strong base,such as a lithium reagent (e.g. LiHMDS) in a solvent such as THF.

The sulfinyl or sulfonyl derivative, e.g. Formula I wherein L is SO orSO₂, may be formed by reacting a 3-thio compounds (I)-E with an oxidizersuch as a peroxide (e.g. oxone or hydrogen peroxide) at room temperaturein a solvent such as acetonitrile and methanol.

Alternatively, a compound of Formula (I)-E can be prepared by reacting,for example, Compounds 1-A with, for example, R₃—X, in a solvent such asDMF and a base such as K₂CO₃ at room temperature or with heating:

wherein all the substituents are as defined previously; X is a leavinggroup such as a halogen, mesylate, or tosylate.Methods of Using Compounds of the Invention

The Compounds of the Invention are useful in the treatment of diseasescharacterized by disruption of or damage to cAMP and cGMP mediatedpathways, e.g., as a result of increased expression of PDE1 or decreasedexpression of cAMP and cGMP due to inhibition or reduced levels ofinducers of cyclic nucleotide synthesis, such as dopamine and nitricoxide (NO). By preventing the degradation of cAMP and cGMP by PDE1B,thereby increasing intracellular levels of cAMP and cGMP, the Compoundsof the Invention potentiate the activity of cyclic nucleotide synthesisinducers.

The invention provides methods of treatment of any one or more of thefollowing conditions:

-   -   (i) Neurodegenerative diseases, including Parkinson's disease,        restless leg, tremors, dyskinesias, Huntington's disease,        Alzheimer's disease, and drug-induced movement disorders;    -   (ii) Mental disorders, including depression, attention deficit        disorder, attention deficit hyperactivity disorder, bipolar        illness, anxiety, sleep disorders, e.g., narcolepsy, cognitive        impairment, dementia, Tourette's syndrome, autism, fragile X        syndrome, psychostimulant withdrawal, and drug addiction;    -   (iii) Circulatory and cardiovascular disorders, including        cerebrovascular disease, stroke, congestive heart disease,        hypertension, pulmonary hypertension, and sexual dysfunction;    -   (iv) Respiratory and inflammatory disorders, including asthma,        chronic obstructive pulmonary disease, and allergic rhinitis, as        well as autoimmune and inflammatory diseases;    -   (v) Any disease or condition characterized by low levels of cAMP        and/or cGMP (or inhibition of cAMP and/or cGMP signaling        pathways) in cells expressing PDE1; and/or    -   (vi) Any disease or condition characterized by reduced dopamine        D1 receptor signaling activity,        comprising administering an effective amount of a Compound of        the Invention, e.g., a compound according to any of Formula I or        1.1-1.135, or a composition comprising a Compound of the        Invention, e.g., a compound according to any of Formula I or        1.1-1.135, or any described in this specification, in free or        pharmaceutically acceptable salt form, to a human or animal        patient in need thereof. In another aspect, the invention        provides a method of treatment of the conditions disclosed above        comprising administering a therapeutically effective amount of a        Compound of Formula II as hereinbefore described, in free or        pharmaceutically acceptable salt form, to a human or animal        patient in need thereof.

In an especially preferred embodiment, the invention provides methods oftreatment or prophylaxis for narcolepsy. In this embodiment, PDE 1Inhibitors may be used as a sole therapeutic agent, but may also be usedin combination or for co-administration with other active agents. Thus,the invention further comprises a method of treating narcolepsycomprising administering simultaneously, sequentially, orcontemporaneously administering therapeutically effective amounts of

-   -   (i) a PDE 1 Inhibitor of the Invention, e.g., a compound        according to any of Formula I or any of 1.1-1.135, or I(i) or        I(ii), or any described in this specification; and    -   (ii) a compound to promote wakefulness or regulate sleep, e.g.,        selected from (a) central nervous system stimulants-amphetamines        and amphetamine like compounds, e.g., methylphenidate,        dextroamphetamine, methamphetamine, and pemoline; (b)        modafinil, (c) antidepressants, e.g., tricyclics (including        imipramine, desipramine, clomipramine, and protriptyline) and        selective serotonin reuptake inhibitors (including fluoxetine        and sertraline); and/or (d) gamma hydroxybutyrate (GHB),        in free or pharmaceutically acceptable salt form, to a human or        animal patient in need thereof. In another embodiment, the        invention provides methods of treatment or prophylaxis for        narcolepsy as herein before described, wherein the PDE1        inhibitor is in a form of a pharmaceutical composition. In still        another embodiment, the methods of treatment or prophylaxis for        narcolepsy as hereinbefore described, comprises administering a        therapeutically effective amount of a Compound of Formula II as        hereinbefore described, in free or pharmaceutically acceptable        salt form, as a sole therapeutic agent or use in combination for        co-administered with another active agent.

In another embodiment, the invention further provides methods oftreatment or prophylaxis of a condition which may be alleviated by theenhancement of the progesterone signaling comprising administering aneffective amount of a Compound of the Invention, e.g., a compoundaccording to any of Formula 1.1-1.135 or Formula I, I(i) or I(ii), orany described in this specification, in free or pharmaceuticallyacceptable salt form, to a human or animal patient in need thereof. Theinvention also provides methods of treatment as disclosed here,comprising administering a therapeutically effective amount of aCompound of Formula II, in free or pharmaceutically acceptable saltform. Disease or condition that may be ameliorated by enhancement ofprogesterone signaling include, but are not limited to, female sexualdysfunction, secondary amenorrhea (e.g., exercise amenorrhoea,anovulation, menopause, menopausal symptoms, hypothyroidism),pre-menstrual syndrome, premature labor, infertility, for exampleinfertility due to repeated miscarriage, irregular menstrual cycles,abnormal uterine bleeding, osteoporosis, autoimmune disease, multiplesclerosis, prostate enlargement, prostate cancer, and hypothyroidism.For example, by enhancing progesterone signaling, the PDE 1 inhibitorsmay be used to encourage egg implantation through effects on the liningof uterus, and to help maintain pregnancy in women who are prone tomiscarriage due to immune response to pregnancy or low progesteronefunction. The novel PDE 1 inhibitors, e.g., as described herein, mayalso be useful to enhance the effectiveness of hormone replacementtherapy, e.g., administered in combination withestrogen/estradiol/estriol and/or progesterone/progestins inpostmenopausal women, and estrogen-induced endometrial hyperplasia andcarcinoma. The methods of the invention are also useful for animalbreeding, for example to induce sexual receptivity and/or estrus in anonhuman female mammal to be bred.

In this embodiment, PDE 1 Inhibitors may be used in the foregoingmethods of treatment or prophylaxis as a sole therapeutic agent, but mayalso be used in combination or for co-administration with other activeagents, for example in conjunction with hormone replacement therapy.Thus, the invention further comprises a method of treating disordersthat may be ameliorated by enhancement of progesterone signalingcomprising administering simultaneously, sequentially, orcontemporaneously administering therapeutically effective amounts of

-   -   (i) a PDE 1 Inhibitor, e.g., a compound according to any of        Formula I, any of 1.1-1.135 or I(i) or I(ii), or any described        in this specification and    -   (ii) a hormone, e.g., selected from estrogen and estrogen        analogues (e.g., estradiol, estriol, estradiol esters) and        progesterone and progesterone analogues (e.g., progestins)        in free or pharmaceutically acceptable salt form, to a human or        animal patient in need thereof. In another embodiment, the        invention provides the method described above wherein the PDE 1        inhibitor is a Compound of Formula II, in free or        pharmaceutically acceptable salt form.

The invention also provides a method for enhancing or potentiatingdopamine D1 intracellular signaling activity in a cell or tissuecomprising contacting said cell or tissue with an amount of a Compoundof the Invention sufficient to inhibit PDE1 B activity.

The invention also provides a method for enhancing or potentiatingprogesterone signaling activity in a cell or tissue comprisingcontacting said cell or tissue with an amount of a Compound of theInvention sufficient to inhibit PDE1B activity.

The invention also provides a method for treating a PDE1-related,especially PDE1B-related disorder, a dopamine D1 receptor intracellularsignaling pathway disorder, or disorders that may be alleviated by theenhancement of the progesterone signaling pathway in a patient in needthereof comprising administering to the patient an effective amount of aCompound of the Invention that inhibits PDE1B, wherein PDE1B activitymodulates phosphorylation of DARPP-32 and/or the GluR1 AMPA receptor.

In another aspect, the invention also provides a method for thetreatment for glaucoma or elevated intraocular pressure comprisingtopical administration of a therapeutically effective amount of aphosphodiesterase type I (PDE1) Inhibitor of the Invention, in free orpharmaceutically acceptable salt form, in an opthalmically compatiblecarrier to the eye of a patient in need thereof. However, treatment mayalternatively include a systemic therapy. Systemic therapy includestreatment that can directly reach the bloodstream, or oral methods ofadministration, for example.

The invention further provides a pharmaceutical composition for topicalophthalmic use comprising a PDE1 inhibitor; for example an ophthalmicsolution, suspension, cream or ointment comprising a PDE1 Inhibitor ofthe Invention, in free or ophthamalogically acceptable salt form, incombination or association with an ophthamologically acceptable diluentor carrier.

Optionally, the PDE1 inhibitor may be administered sequentially orsimultaneously with a second drug useful for treatment of glaucoma orelevated intraocular pressure. Where two active agents are administered,the therapeutically effective amount of each agent may be below theamount needed for activity as monotherapy. Accordingly, a subthresholdamount (i.e., an amount below the level necessary for efficacy asmonotherapy) may be considered therapeutically effective and also mayalso be referred alternatively as an effective amount. Indeed, anadvantage of administering different agents with different mechanisms ofaction and different side effect profiles may be to reduce the dosageand side effects of either or both agents, as well as to enhance orpotentiate their activity as monotherapy.

The invention thus provides the method of treatment of a conditionselected from glaucoma and elevated intraocular pressure comprisingadministering to a patient in need thereof an effective amount, e.g., asubthreshold amount, of an agent known to lower intraocular pressureconcomitantly, simultaneously or sequentially with an effective amount,e.g., a subthreshold amount, of a PDE1 Inhibitor of the Invention, infree or pharmaceutically acceptable salt form, such that amount of theagent known to lower intraocular pressure and the amount of the PDE 1inhibitor in combination are effective to treat the condition.

In one embodiment, one or both of the agents are administered topicallyto the eye. Thus the invention provides a method of reducing the sideeffects of treatment of glaucoma or elevated intraocular pressure byadministering a reduced dose of an agent known to lower intraocularpressure concomitantly, simultaneously or sequentially with an effectiveamount of a PDE1 inhibitor. However, methods other than topicaladministration, such as systemic therapeutic administration, may also beutilized.

The optional additional agent or agents for use in combination with aPDE1 inhibitor may, for example, be selected from the existing drugscomprise typically of instillation of a prostaglandin, pilocarpine,epinephrine, or topical beta-blocker treatment, e.g. with timolol, aswell as systemically administered inhibitors of carbonic anhydrase, e.g.acetazolamide. Cholinesterase inhibitors such as physostigmine andechothiopate may also be employed and have an effect similar to that ofpilocarpine. Drugs currently used to treat glaucoma thus include, e.g.,

-   -   1. Prostaglandin analogs such as latanoprost (Xalatan),        bimatoprost (Lumigan) and travoprost (Travatan), which increase        uveoscleral outflow of aqueous humor. Bimatoprost also increases        trabecular outflow.    -   2. Topical beta-adrenergic receptor antagonists such as timolol,        levobunolol (Betagan), and betaxolol, which decrease aqueous        humor production by the ciliary body.    -   3. Alpha₂-adrenergic agonists such as brimonidine (Alphagan),        which work by a dual mechanism, decreasing aqueous production        and increasing uveo-scleral outflow.    -   4. Less-selective sympathomimetics like epinephrine and        dipivefrin (Propine) increase outflow of aqueous humor through        trabecular meshwork and possibly through uveoscleral outflow        pathway, probably by a beta₂-agonist action.    -   5. Miotic agents (parasympathomimetics) like pilocarpine work by        contraction of the ciliary muscle, tightening the trabecular        meshwork and allowing increased outflow of the aqueous humour.    -   6. Carbonic anhydrase inhibitors like dorzolamide (Trusopt),        brinzolamide (Azopt), acetazolamide (Diamox) lower secretion of        aqueous humor by inhibiting carbonic anhydrase in the ciliary        body.    -   7. Physostigmine is also used to treat glaucoma and delayed        gastric emptying.

For example, the invention provides pharmaceutical compositionscomprising a PDE1 Inhibitor of the Invention and an agent selected from(i) the prostanoids, unoprostone, latanoprost, travoprost, orbimatoprost; (ii) an alpha adrenergic agonist such as brimonidine,apraclonidine, or dipivefrin and (iii) a muscarinic agonist, such aspilocarpine. For example, the invention provides ophthalmic formulationscomprising a PDE-1 Inhibitor of the Invention together with bimatoprost,abrimonidine, brimonidine, timolol, or combinations thereof, in free orophthamalogically acceptable salt form, in combination or associationwith an ophthamologically acceptable diluent or carrier. In addition toselecting a combination, however, a person of ordinary skill in the artcan select an appropriate selective receptor subtype agonist orantagonist. For example, for alpha adrenergic agonist, one can select anagonist selective for an alpha 1 adrenergic receptor, or an agonistselective for an alpha₂ adrenergic receptor such as brimonidine, forexample. For a beta-adrenergic receptor antagonist, one can select anantagonist selective for either β₁, or β₂, or β₃, depending on theappropriate therapeutic application. One can also select a muscarinicagonist selective for a particular receptor subtype such as M₁-M₅.

The PDE 1 inhibitor may be administered in the form of an ophthalmiccomposition, which includes an ophthalmic solution, cream or ointment.The ophthalmic composition may additionally include anintraocular-pressure lowering agent.

In yet another example, the PDE-1 Inhibitors disclosed may be combinedwith a subthreshold amount of an intraocular pressure-lowering agentwhich may be a bimatoprost ophthalmic solution, a brimonidine tartrateophthalmic solution, or brimonidine tartrate/timolol maleate ophthalmicsolution.

In addition to the above-mentioned methods, it has also beensurprisingly discovered that PDE1 inhibitors are useful to treatpsychosis, for example, any conditions characterized by psychoticsymptoms such as hallucinations, paranoid or bizarre delusions, ordisorganized speech and thinking, e.g., schizophrenia, schizoaffectivedisorder, schizophreniform disorder, psychotic disorder, delusionaldisorder, and mania, such as in acute manic episodes and bipolardisorder. Without intending to be bound by any theory, it is believedthat typical and atypical antipsychotic drugs such as clozapineprimarily have their antagonistic activity at the dopamine D2 receptor.PDE1 inhibitors, however, primarily act to enhance signaling at thedopamine D1 receptor. By enhancing D1 receptor signaling, PDE1inhibitors can increase NMDA receptor function in various brain regions,for example in nucleus accumbens neurons and in the prefrontal cortex.This enhancement of function may be seen for example in NMDA receptorscontaining the NR2B subunit, and may occur e.g., via activation of theSrc and protein kinase A family of kinases.

Therefore, the invention provides a new method for the treatment ofpsychosis, e.g., schizophrenia, schizoaffective disorder,schizophreniform disorder, psychotic disorder, delusional disorder, andmania, such as in acute manic episodes and bipolar disorder, comprisingadministering a therapeutically effective amount of aphosphodiesterase-1 (PDE1) Inhibitor of the Invention, in free orpharmaceutically acceptable salt form, to a patient in need thereof.

PDE 1 Inhibitors may be used in the foregoing methods of treatmentprophylaxis as a sole therapeutic agent, but may also be used incombination or for co-administration with other active agents. Thus, theinvention further comprises a method of treating psychosis, e.g.,schizophrenia, schizoaffective disorder, schizophreniform disorder,psychotic disorder, delusional disorder, or mania, comprisingadministering simultaneously, sequentially, or contemporaneouslyadministering therapeutically effective amounts of:

-   -   (i) a PDE 1 Inhibitor of the invention, in free or        pharmaceutically acceptable salt form; and    -   (ii) an antipsychotic, e.g.,        -   Typical antipsychotics, e.g.,            -   Butyrophenones, e.g. Haloperidol (Haldol, Serenace),                Droperidol (Droleptan);            -   Phenothiazines, e.g., Chlorpromazine (Thorazine,                Largactil), Fluphenazine (Prolixin), Perphenazine                (Trilafon), Prochlorperazine (Compazine), Thioridazine                (Mellaril, Melleril), Trifluoperazine (Stelazine),                Mesoridazine, Periciazine, Promazine, Triflupromazine                (Vesprin), Levomepromazine (Nozinan), Promethazine                (Phenergan), Pimozide (Orap);            -   Thioxanthenes, e.g., Chlorprothixene, Flupenthixol                (Depixol, Fluanxol), Thiothixene (Navane),                Zuclopenthixol (Clopixol, Acuphase);        -   Atypical antipsychotics, e.g.,            -   Clozapine (Clozaril), Olanzapine (Zyprexa), Risperidone                (Risperdal), Quetiapine (Seroquel), Ziprasidone                (Geodon), Amisulpride (Solian), Paliperidone (Invega),                Aripiprazole (Abilify), Bifeprunox; norclozapine,    -   in free or pharmaceutically acceptable salt form, to a patient        in need thereof.

In a particular embodiment, the Compounds of the Invention areparticularly useful for the treatment or prophylaxis of schizophrenia.

Compounds of the Invention, in free or pharmaceutically acceptable saltform, are particularly useful for the treatment of Parkinson's disease,schizophrenia, narcolepsy, glaucoma and female sexual dysfunction.

In still another aspect, the invention provides a method of lengtheningor enhancing growth of the eyelashes by administering an effectiveamount of a prostaglandin analogue, e.g., bimatoprost, concomitantly,simultaneously or sequentially with an effective amount of a PDE 1inhibitor of the Invention, in free or pharmaceutically acceptable saltform, to the eye of a patient in need thereof.

In yet another aspect, the invention provides a method for the treatmentor prophylaxis of traumatic brain injury comprising administering atherapeutically effective amount of a PDE1 inhibitor of the invention,in free or pharmaceutically acceptable salt form, to a patient in needthereof. Traumatic brain injury (TBI) encompasses primary injury as wellas secondary injury, including both focal and diffuse brain injuries.Secondary injuries are multiple, parallel, interacting andinterdependent cascades of biological reactions arising from discretesubcellular processes (e.g., toxicity due to reactive oxygen species,overstimulation of glutamate receptors, excessive influx of calcium andinflammatory upregulation) which are caused or exacerbated by theinflammatory response and progress after the initial (primary) injury.Abnormal calcium homeostasis is believed to be a critical component ofthe progression of secondary injury in both grey and white matter. For areview of TBI, see Park et al., CMAJ (2008) 178(9):1163-1170, thecontents of which are incorporated herein in their entirety. Studieshave shown that the cAMP-PKA signaling cascade is downregulated afterTBI and treatment of PDE IV inhibitors such as rolipram to raise orrestore cAMP level improves histopathological outcome and decreasesinflammation after TBI. As Compounds of the present invention is a PDE1inhibitor, it is believed that these compounds are also useful for thetreatment of TBI, e.g., by restoring cAMP level and/or calciumhomeostasis after traumatic brain injury.

The present invention also provides

-   -   (i) a Compound of the Invention for use as a pharmaceutical, for        example for use in any method or in the treatment of any disease        or condition as hereinbefore set forth,    -   (ii) the use of a Compound of the Invention in the manufacture        of a medicament for treating any disease or condition as        hereinbefore set forth,    -   (iii) a pharmaceutical composition comprising a Compound of the        Invention in combination or association with a pharmaceutically        acceptable diluent or carrier, and    -   (iv) a pharmaceutical composition comprising a Compound of the        Invention in combination or association with a pharmaceutically        acceptable diluent or carrier for use in the treatment of any        disease or condition as hereinbefore set forth.

Therefore, the invention provides use of a Compound of the Invention forthe manufacture of a medicament for the treatment or prophylactictreatment of the following diseases: Parkinson's disease, restless leg,tremors, dyskinesias, Huntington's disease, Alzheimer's disease, anddrug-induced movement disorders; depression, attention deficit disorder,attention deficit hyperactivity disorder, bipolar illness, anxiety,sleep disorder, narcolepsy, cognitive impairment, dementia, Tourette'ssyndrome, autism, fragile X syndrome, psychostimulant withdrawal, and/ordrug addiction; cerebrovascular disease, stroke, congestive heartdisease, hypertension, pulmonary hypertension, and/or sexualdysfunction; asthma, chronic obstructive pulmonary disease, and/orallergic rhinitis, as well as autoimmune and inflammatory diseases;and/or female sexual dysfunction, exercise amenorrhoea, anovulation,menopause, menopausal symptoms, hypothyroidism, pre-menstrual syndrome,premature labor, infertility, irregular menstrual cycles, abnormaluterine bleeding, osteoporosis, multiple sclerosis, prostateenlargement, prostate cancer, hypothyroidism, estrogen-inducedendometrial hyperplasia or carcinoma; and/or any disease or conditioncharacterized by low levels of cAMP and/or cGMP (or inhibition of cAMPand/or cGMP signaling pathways) in cells expressing PDE1, and/or byreduced dopamine D1 receptor signaling activity; and/or any disease orcondition that may be ameliorated by the enhancement of progesteronesignaling.

The invention also provides use of a Compound of the Invention, in freeor pharmaceutically acceptable salt form, for the manufacture of amedicament for the treatment or prophylactic treatment of:

-   -   a) glaucoma or elevated intraocular pressure,    -   b) psychosis, for example, any conditions characterized by        psychotic symptoms such as hallucinations, paranoid or bizarre        delusions, or disorganized speech and thinking, e.g.,        schizophrenia, schizoaffective disorder, schizophreniform        disorder, psychotic disorder, delusional disorder, and mania,        such as in acute manic episodes and bipolar disorder,    -   c) traumatic brain injury.

The phrase “Compounds of the Invention” or “PDE 1 inhibitors of theInvention” encompasses any and all of the compounds disclosed withinthis specification.

The words “treatment” and “treating” are to be understood accordingly asembracing prophylaxis and treatment or amelioration of symptoms ofdisease as well as treatment of the cause of the disease

For methods of treatment, the word “effective amount” is intended toencompass a therapeutically effective amount to treat a specific diseaseor disorder.

The term “pulmonary hypertension” is intended to encompass pulmonaryarterial hypertension.

The term “patient” include human or non-human (i.e., animal) patient. Inparticular embodiment, the invention encompasses both human andnonhuman. In another embodiment, the invention encompasses nonhuman. Inother embodiment, the term encompasses human.

The term “comprising” as used in this disclosure is intended to beopen-ended and does not exclude additional, unrecited elements or methodsteps.

Compounds of the Invention are in particular useful for the treatment ofParkinson's disease, narcolepsy and female sexual dysfunction.

Compounds of the Invention may be used as a sole therapeutic agent, butmay also be used in combination or for co-administration with otheractive agents.

For example, as Compounds of the Invention potentiate the activity of D1agonists, such as dopamine, they may be simultaneously, sequentially, orcontemporaneously administered with conventional dopaminergicmedications, such as levodopa and levodopa adjuncts (carbidopa, COMTinhibitors, MAO-B inhibitors), dopamine agonists, and anticholinergics,e.g., in the treatment of a patient having Parkinson's disease. Inaddition, the novel PDE 1 inhibitors of the Invention, e.g., theCompounds of the Invention as described herein, may also be administeredin combination with estrogen/estradiol/estriol and/orprogesterone/progestins to enhance the effectiveness of hormonereplacement therapy or treatment of estrogen-induced endometrialhyperplasia or carcinoma.

Dosages employed in practicing the present invention will of course varydepending, e.g. on the particular disease or condition to be treated,the particular Compound of the Invention used, the mode ofadministration, and the therapy desired. Compounds of the Invention maybe administered by any suitable route, including orally, parenterally,transdermally, or by inhalation, but are preferably administered orally.In general, satisfactory results, e.g. for the treatment of diseases ashereinbefore set forth are indicated to be obtained on oraladministration at dosages of the order from about 0.01 to 2.0 mg/kg. Inlarger mammals, for example humans, an indicated daily dosage for oraladministration will accordingly be in the range of from about 0.75 to150 mg, conveniently administered once, or in divided doses 2 to 4times, daily or in sustained release form. Unit dosage forms for oraladministration thus for example may comprise from about 0.2 to 75 or 150mg, e.g. from about 0.2 or 2.0 to 50, 75 or 100 mg of a Compound of theInvention, together with a pharmaceutically acceptable diluent orcarrier therefor.

Pharmaceutical compositions comprising Compounds of the Invention may beprepared using conventional diluents or excipients and techniques knownin the galenic art. Thus oral dosage forms may include tablets,capsules, solutions, suspensions and the like.

EXAMPLES

The synthetic methods for various Compounds of the Present Invention areillustrated below. Other compounds of the Invention and their salts maybe made using the methods as similarly described below and/or by methodssimilar to those generally described in the detailed description and bymethods known in the chemical art.

Example 12-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

1)2-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

5-methyl-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione (200mg, 0.847 mmol), 1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole (202 mg,0.847 mmol) and K₂CO₃ (117 mg, 0.847 mmol) are suspended in 5 mL ofanhydrous DMF. The reaction mixture is stirred at room temperature for 5h, and then evaporated to dryness under reduced pressure. The residue istreated with water, and then extracted with dichloromethane three times.The combined organic phase is dried with anhydrous sodium sulfate,filtered, and then evaporated to dryness to give 337 mg of crudeproduct, which is used in the next step without further purification. MS(ESI) m/z 394.2 [M+H]⁺.

2)2-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

2-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione(52 mg, 0.132 mmol) and methyl disulfide (12 μL, 0.13 mmol) aredissolved in 2 mL of anhydrous CH₂Cl₂, and then 1.0 M LiHMDS (190 μL,0.19 mmol) in THF is added dropwise. The reaction mixture is stirred atroom temperature for 30 min, and then quenched with saturated ammoniumchloride aqueous solution. After routine workup, the obtained crudeproduct is purified by silica gel column chromatography to give pureproduct as off-white solids. MS (ESI) m/z 440.2 [M+H]⁺.

Example 25-methyl-3-(methylthio)-7-neopentyl-2-(4-(trifluoromethyl)benzyl)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 1wherein 1-(bromomethyl)-4-(trifluoromethyl)benzene is used in step 1instead of 1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z441.2 [M+H]⁺.

Example 35-methyl-7-neopentyl-3-(phenylthio)-2-(4-(trifluoromethyl)benzyl)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 1wherein 1-(bromomethyl)-4-(trifluoromethyl)benzene is used in step 1instead of 1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole, and phenyldisulfide is used in step 2 instead of methyl disulfide. MS (ESI) m/z503.2 [M+H]⁺.

Example 42-(4-methoxybenzyl)-5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 1wherein 4-methoxybenzyl bromide is used in step 1 instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole, and phenyl disulfide isused in step 2 instead of methyl disulfide. MS (ESI) m/z 465.2 [M+H]⁺.

Example 52-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

2-(4-methoxybenzyl)-5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione(2.7 g, 5.9 mmol) is dissolved in CH₂Cl₂ (20 mL) containing TFA (4.2 mL)and TFMSA (1.0 mL). The mixture is stirred at room temperatureovernight. Solvents are removed, and the residue is dissolved in ethylacetate (250 mL), followed by washing with saturate NaHCO₃ and watersuccessively. After dried over anhydrous sodium sulfate, the organicphase is evaporated to dryness. The obtained crude product is used inthe next step without further purification.

Crude5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione(40 mg, 0.12 mmol), 1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole (28 mg,0.12 mmol) and K₂CO₃ (16 mg, 0.12 mmol) are suspended in 5 mL ofanhydrous DMF. The reaction mixture is stirred at room temperatureovernight, and then evaporated to dryness under reduced pressure. Theresidue is purified by silica gel column chromatography to give pureproduct as white solids. MS (ESI) m/z 502.2 [M+H]⁺.

Example 62-(4-methoxybenzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 1wherein 4-methoxybenzyl bromide is used in step 1 instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z 403.2 [M+H]⁺.

Example 72-(4-(1H-pyrazol-1-yl)benzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 5wherein2-(4-methoxybenzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dioneis used instead of2-(4-methoxybenzyl)-5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione,and 1-(4-(bromomethyl)phenyl)-1H-pyrazole is used instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z 439.2 [M+H]⁺.

Example 85-methyl-2-(4-(methylsulfonyl)benzyl)-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 5wherein 1-(bromomethyl)-4-(methylsulfonyl)benzene is used instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z 513.2 [M+H]⁺.

Example 95-methyl-7-neopentyl-3-(phenylthio)-2-(4-(pyridin-2-yl)benzyl)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 1wherein 2-(4-(bromomethyl)phenyl)pyridine is used in step 1 instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole, and phenyl disulfide isused in step 2 instead of methyl disulfide. MS (ESI) m/z 512.3 [M+H]⁺.

Example 105-methyl-2-(4-(1-methylpiperidin-2-yl)benzyl)-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 5wherein 2-(4-(chloromethyl)phenyl)-1-methylpiperidine is used instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z 532.3 [M+H]⁺.

Example 115-methyl-2-(4-(methylsulfonyl)benzyl)-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 5wherein2-(4-methoxybenzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dioneis used instead of2-(4-methoxybenzyl)-5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione,and 1-(bromomethyl)-4-(methylsulfonyl)benzene is used instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z 451.1 [M+H]⁺.

Example 125-methyl-3-(methylsulfinyl)-2-(4-(methylsulfonyl)benzyl)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

5-methyl-2-(4-(methylsulfonyl)benzyl)-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione(11.4 mg, 0.022 mmol) is dissolved in CH₂Cl₂ (200 μL) and CH₃CN (100μL), and then 30% H₂O₂ aqueous solution (75 μL, 0.66 mmol) is added,followed by acetic acid (6.6 mg, 0.11 mmol). The reaction mixture isstirred at room temperature over a weekend, and then purified by asemi-preparative HPLC to give 6 mg of product as white solids. MS (ESI)m/z 467.1 [M+H]⁺.

Example 132-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-3-(methylsulfinyl)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

2-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione(16 mg, 0.036 mmol) is dissolved in CH₂Cl₂ (500 μL) and MeOH (500 μL),and then an aqueous solution of Oxone (22.4 mg, 0.036 mmol) is added.The reaction mixture is stirred at room temperature for 2 days, and thenpurified by a semi-preparative HPLC to give 8 mg of product as off-whitesolids. MS (ESI) m/z 456.2 [M+H]⁺.

Example 142-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-3-(methylsulfonyl)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is the same as EXAMPLE 13.2-(4-(1H-1,2,4-triazol-1-yl)benzyl)-5-methyl-3-(methylsulfonyl)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dioneis obtained as a minor product of the reaction. MS (ESI) m/z 472.2[M+H]⁺.

Example 155-methyl-2-(4-(1-methylpiperidin-2-yl)benzyl)-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione

The synthetic procedure of this compound is analogous to EXAMPLE 5wherein2-(4-methoxybenzyl)-5-methyl-3-(methylthio)-7-neopentyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dioneis used instead of2-(4-methoxybenzyl)-5-methyl-7-neopentyl-3-(phenylthio)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione,and 2-(4-(chloromethyl)phenyl)-1-methylpiperidine is used instead of1-(4-(bromomethyl)phenyl)-1H-1,2,4-triazole. MS (ESI) m/z 439.2 [M+H]⁺.

Example 16 Measurement of PDE1B Inhibition In Vitro Using IMAPPhosphodiesterase Assay Kit

Phosphodiesterase 1B (PDE1B) is a calcium/calmodulin dependentphosphodiesterase enzyme that converts cyclic guanosine monophosphate(cGMP) to 5′-guanosine monophosphate (5′-GMP). PDE1B can also convert amodified cGMP substrate, such as the fluorescent moleculecGMP-fluorescein, to the corresponding GMP-fluorescein. The generationof GMP-fluorescein from cGMP-fluorescein can be quantitated, using, forexample, the IMAP (Molecular Devices, Sunnyvale, Calif.)immobilized-metal affinity particle reagent.

Briefly, the IMAP reagent binds with high affinity to the free5′-phosphate that is found in GMP-fluorescein and not incGMP-fluorescein. The resulting GMP-fluorescein-IMAP complex is largerelative to cGMP-fluorescein. Small fluorophores that are bound up in alarge, slowly tumbling, complex can be distinguished from unboundfluorophores, because the photons emitted as they fluoresce retain thesame polarity as the photons used to excite the fluorescence.

In the phosphodiesterase assay, cGMP-fluorescein, which cannot be boundto IMAP, and therefore retains little fluorescence polarization, isconverted to GMP-fluorescein, which, when bound to IMAP, yields a largeincrease in fluorescence polarization (Δmp). Inhibition ofphosphodiesterase, therefore, is detected as a decrease in Δmp.

Enzyme Assay

Materials: All chemicals are available from Sigma-Aldrich (St. Louis,Mo.) except for IMAP reagents (reaction buffer, binding buffer, FL-GMPand IMAP beads), which are available from Molecular Devices (Sunnyvale,Calif.).

Assay: 3′,5′-cyclic-nucleotide-specific bovine brain phosphodiesterase(Sigma, St. Louis, Mo.) is reconstituted with 50% glycerol to 2.5 U/ml.One unit of enzyme will hydrolyze 1.0 μmole of 3′,5′-cAMP to 5′-AMP permin at pH 7.5 at 30° C. One part enzyme is added to 1999 parts reactionbuffer (30 μM CaCl₂, 10 U/ml of calmodulin (Sigma P2277), 10 mM Tris-HClpH 7.2, 10 mM MgCl₂, 0.1% BSA, 0.05% NaN₃) to yield a finalconcentration of 1.25 mU/ml. 99 μl of diluted enzyme solution is addedinto each well in a flat bottom 96-well polystyrene plate to which 1 μlof test compound dissolved in 100% DMSO is added. Selected Compounds ofthe Invention are mixed and pre-incubated with the enzyme for 10 min atroom temperature.

The FL-GMP conversion reaction is initiated by combining 4 parts enzymeand inhibitor mix with 1 part substrate solution (0.225 μM) in a384-well microtiter plate. The reaction is incubated in dark at roomtemperature for 15 min. The reaction is halted by addition of 60 μl ofbinding reagent (1:400 dilution of IMAP beads in binding buffersupplemented with 1:1800 dilution of antifoam) to each well of the384-well plate. The plate is incubated at room temperature for 1 hour toallow IMAP binding to proceed to completion, and then placed in anEnvision multimode microplate reader (PerkinElmer, Shelton, Conn.) tomeasure the fluorescence polarization (Δmp).

A decrease in GMP concentration, measured as decreased Amp, isindicative of inhibition of PDE activity. IC₅₀ values are determined bymeasuring enzyme activity in the presence of 8 to 16 concentrations ofcompound ranging from 0.0037 nM to 80,000 nM and then plotting drugconcentration versus ΔmP, which allows IC₅₀ values to be estimated usingnonlinear regression software (XLFit; IDBS, Cambridge, Mass.).

The Compounds of the Invention may be selected and tested in an assay asdescribed or similarly described herein for PDE1 inhibitory activity.The exemplified compounds of the invention generally have IC₅₀ values ofless than 5 μM, some less than 1 μM, some less than 250 nM, some withPDE1A activities.

Example 17 PDE1 Inhibitor Effect on Sexual Response in Female Rats

The effect of PDE1 inhibitors on Lordosis Response in female rats ismeasured as described in Mani, et al., Science (2000) 287: 1053.Ovariectomized and cannulated wild-type rats are primed with 2 μgestrogen followed 24 hours later by intracerebroventricular (icy)injection of progesterone (2 μg), PDE1 inhibitors of the presentinvention (0.1 mg, 1.0 mg or 2.5 mg) or sesame oil vehicle (control).The rats are tested for lordosis response in the presence of male rats.Lordosis response is quantified by the lordosis quotient (LQ=number oflordosis/10 mounts×100). The LQ for estrogen-primed female ratsreceiving Compounds of the Invention, at 0.1 mg, will likely be similarto estrogen-primed rats receiving progesterone and higher than forestrogen-primed rats receiving vehicle.

What is claimed is:
 1. A compound of formula I:

wherein (i) L is S or SO₂; (ii) R₁ is H or C₁₋₆alkyl; (iii) R₂ is H, C₁₋₆alkyl wherein said alkyl group is optionally substituted with halo or hydroxy, —C₀₋₄alkyl-C₃₋₈cycloalkyl optionally substituted with one or more amino, wherein said cycloalkyl optionally contains one or more heteroatom selected from N and O and is optionally substituted with C₁₋₆alkyl, haloC₁₋₆alkyl, N(R₁₄)(R₁₅)—C₁₋₆alkyl, hydroxyC₁₋₆alkyl, arylC₀₋₆alkyl, heteroarylC₁₋₆alkyl, C₁₋₆alkoxyarylC₁₋₆alkyl; (iv) R₃ is 1) -D-E-F wherein: D is a single bond, C₁₋₆alkylene or arylalkylene, E is a single bond, C₁₋₄alkylene, —C₀₋₄alkylarylene, wherein the arylene group is optionally substituted with halo, heteroarylene, aminoC₁₋₆alkylene, amino, C₃₋₈cycloalkylene optionally containing one or more heteroatom selected from N or O, F is haloC₁₋₆alkyl, aryl, C₃₋₈cycloalkyl optionally containing at least one atom selected from a group consisting of N or O, and optionally substituted with C₁₋₆alkyl, heteroaryl optionally substituted with C₁₋₆alkyl, halo or haloC₁₋₆alkyl, alkoxadiazoly, amino, O-haloC₁₋₆alkyl, C₁₋₆alkylsulfonyl, —C(O)—R₁₃, —N(R₁₄)(R₁₅); 2) a haloalkyl substituted heteroarylaklyl; or 3) attached to one of the nitrogens on the pyrazolo portion of Formula I and is a moiety of Formula A

wherein X, Y and Z are, independently, N or C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is C₃₋₈cycloalkyl, haloC₁₋₆alkyl, aryl, heteroaryl, C₁₋₆alkyl sulfonyl, arylcarbonyl alkoxadiazolyl, heteroarylcarbonyl, alkoxycarbonyl, or aminocarbonyl; provided that when X, Y or Z is nitrogen, R₈, R₉ or R₁₀, respectively, is not present; (v) R₄ is selected from: H, C₁₋₆alkyl, C₃₋₈cycloalkyl, C₃₋₈heterocycloalkyl, aryl or heteroaryl wherein said aryl or heteroaryl is optionally substituted with halo, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group; (vi) R₁₃ is —N(R₁₄)(R₁₅), C₁₋₆alkyl, —OC₁₋₆alkyl, haloC₁₋₆alkyl, aryl, or heteroaryl; and (vii) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl, in free or salt form.
 2. The compound according to claim 1 selected from:

in free or salt form.
 3. The compound according to claim 1, selected from any of the following:

in free or salt form.
 4. The compound according to claim 1, which is a compound of formula I:

wherein (i) L is S or SO₂; (ii) R₁ is H or C₁₋₆alkyl; (iii) R₂ is H, C₁₋₆alkyl wherein said alkyl group is optionally substituted with halo or hydroxy, —C₀₋₄alkyl-C₃₋₈cycloalkyl optionally substituted with one or more amino, wherein said cycloalkyl optionally contains one or more heteroatom selected from N and O and is optionally substituted with C₁₋₆alkyl, haloC₁₋₆alkyl, N(R₁₄)(R₁₅)—C₁₋₆alkyl, hydroxyC₁₋₆alkyl, arylC₀₋₆alkyl, heteroarylC₁₋₆alkyl, C₁₋₆alkoxyarylC₁₋₆alkyl; (iv) R₃ is 1) -D-E-F wherein: D is a C₁₋₆alkylene, E is a phenylene optionally substituted with halo, F is haloC₁₋₆alkyl, aryl, C₃₋₈cycloalkyl optionally containing at least one atom selected from a group consisting of N or O, and optionally substituted with C₁₋₆alkyl, heteroaryl optionally substituted with C₁₋₆alkyl, halo or haloC₁₋₆alkyl, alkoxadiazolyl, amino, —O-haloC₁₋₆alkyl, C₁₋₆alkylsulfonyl, —C(O)—R₁₃, —N(R₁₄)(R₁₅); 2) or attached to one of the nitrogens on the pyrazolo portion of Formula I and is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is C₁₋₈cycloalkyl, haloC₁₋₆alkyl, aryl, heteroaryl, C₁₋₆alkyl sulfonyl , arylcarbonyl alkoxadiazolyl, heteroarylcarbonyl, alkoxycarbonyl, or aminocarbonyl; (v) R₄ is selected from: H, C₁₋₆alkyl, C₃₋₈cycloalkyl, C₃₋₈heterocycloalkyl, aryl or heteroaryl wherein said aryl or heteroaryl is optionally substituted with halo, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group; (vi) R₁₃ is —N(R₁₄)(R₁₅), C₁₋₆alkyl, —OC₁₋₆alkyl, haloC₁₋₆alkyl, aryl, or heteroaryl; and (vii) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl, in free or salt form.
 5. The compound according to claim 4, wherein said compound is a compound of Formula II:

wherein (i) L is S or SO₂; (ii) R₁ is H or C₁₋₆alkyl; (iii) R₂ is H, C₁₋₆alkyl wherein said alkyl group is optionally substituted with halo or hydroxy, —C₀₋₄alkyl-C₃₋₈cycloalkyl optionally substituted with one or more amino, wherein said cycloalkyl optionally contains one or more heteroatom selected from N and O and is optionally substituted with C₁₋₆alkyl, haloC₁₋₆alkyl, N(R₁₄)(R₁₅)—C₁₋₆alkyl, hydroxyC₁₋₆alkyl, arylC₀₋₆alkyl, heteroarylC₁₋₆alkyl, C₁₋₆alkoxyarylC₁₋₆alkyl; (iv) R₃ is attached to one of the nitrogens on the pyrazolo portion of Formula II and is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is C₁₋₈cycloalkyl, haloC₁₋₆alkyl, aryl, heteroaryl, alkoxadiazolyl, alkyl sulfonyl, arylcarbonyl heteroarylcarbonyl, alkoxycarbonyl, or aminocarbonyl; (v) R₄ is H, C₁₋₆alkyl, C₃₋₈cycloalkyl, C₃₋₈heterocycloalkyl, aryl or heteroaryl wherein said aryl or heteroaryl is optionally substituted with halo, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group; (vi) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl; in free or salt form.
 6. The compound according to claim 5, wherein: R₄ is: C₁₋₆alkyl, C₃₋₈cycloalkyl, C₃₋₈heterocycloalkyl, aryl or heteroaryl wherein said aryl or heteroaryl is optionally substituted with halo, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group; and R₃ is attached to one of the nitrogens on the pyrazolo portion of Formula II and is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is C₃₋₈cycloalkyl aryl, or heteroaryl, alkoxadiazolyl; in free or salt form.
 7. The compound according to claim 4, wherein the compound of Formula I is:

and R₂ is C₁₋₆alkyl wherein said alkyl group is optionally substituted with halo or hydroxy, in free or salt form.
 8. The compound according to claim 7, wherein R₄ is C₁₋₆alkyl, in free or salt form.
 9. The compound according to claim 8, wherein R₃ is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is 1,2,4-triazol-1-yl, in free or salt form.
 10. The compound according to claim 8, wherein R₃ is -D-E-F wherein F is heteroaryl optionally substituted with C₁₋₆alkyl, halo or haloC₁₋₆alkyl; or F is C₃₋₈cycloalkyl optionally containing at least one atom selected from a group consisting of N or O, and optionally substituted with C₁₋₆alkyl, in free or salt form.
 11. The compound according to claim 10, wherein R₂ is 2,2-dimethylpropyl, in free or salt form.
 12. The compound according to claim 11, wherein said compound is:

in free or salt form.
 13. The compound according to claim 7, wherein R₄ is aryl optionally substituted with halo, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group, in free or salt form.
 14. The compound according to claim 7, wherein R₄ is phenyl, in free or salt form.
 15. The compound according to claim 14, wherein R₃ is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is methylsulfonyl, in free or salt form.
 16. The compound according to claim 14, wherein R₃ is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is trifluoromethyl, in free or salt form.
 17. The compound according to claim 14, wherein R₃ is a moiety of Formula A

wherein X, Y and Z are C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is 1,2,4-triazol-1-yl, in free or salt form.
 18. The compound according to claim 14, wherein R₃ is -D-E-F wherein F is heteroaryl optionally substituted with C₁₋₆alkyl, halo or haloC₁₋₆alkyl; or F is C₁₋₈cycloalkyl optionally containing at least one atom selected from a group consisting of N or O, and optionally substituted with C₁₋₆alkyl, in free or salt form.
 19. The compound according to claim 18, wherein R₂ is 2,2-dimethylpropyl, in free or salt form.
 20. The compound according to claim 4, wherein said compound is:

in free or salt form.
 21. The compound according to claim 1, wherein said compound is a compound of Formula II:

wherein (i) L is S or SO₂; (ii) R₁ is H or C₁₋₆alkyl; (iii) R₂ is H, C₁₋₆alkyl wherein said alkyl group is optionally substituted with halo or hydroxy, —C₀₋₄alkyl-C₃₋₈cycloalkyl optionally substituted with one or more amino, wherein said cycloalkyl optionally contains one or more heteroatom selected from N and O and is optionally substituted with C₁₋₆alkyl, haloC₁₋₆alkyl, N(R₁₄)(R₁₅)—C₁₋₆alkyl, hydroxyC₁₋₆alkyl, arylC₀₋₆alkyl, heteroarylC₁₋₆alkyl, C₁₋₆alkoxyarylC₁₋₆alkyl; (iv) R₃ is attached to one of the nitrogens on the pyrazolo portion of Formula II and is a moiety of Formula A

wherein X, Y and Z are, independently, N or C, and R₈, R₉, R₁₁ and R₁₂ are independently H or halogen; and R₁₀ is C₃₋₈cycloalkyl, haloC₁₋₆alkyl, aryl, heteroaryl, alkoxadiazolyl, alkyl sulfonyl, arylcarbonyl heteroarylcarbonyl, alkoxycarbonyl, or aminocarbonyl, Provided that when X, Y or Z is nitrogen, R₈, R₉ or R₁₀, respectively, is not present; (v) R₄ is H, C₁₋₆alkyl, C₃₋₈cycloalkyl, C₃₋₈heterocycloalkyl, aryl or heteroaryl wherein said aryl or heteroaryl is optionally substituted with halo, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy or another aryl group; (vi) R₁₄ and R₁₅ are independently H or C₁₋₆alkyl; in free or salt form.
 22. A compound of formula:

in free or salt form.
 23. A pharmaceutical composition comprising a compound according to claim 5, in free or pharmaceutically acceptable salt form, in admixture with a pharmaceutically acceptable diluent or carrier. 